Polaris based GPUs are not enough for that display. The 21.5 can't have memory upgraded and storage is a bastard to upgrade (if its even possible).
If you want more than 16 GB of RAM you're forced into the 27" even if you don't want a screen that big (or even a screen at all) and forced into a discrete GPU that you don't want because it's not good enough (would rather plug in one of the Vega cards i already own from my PC - rendering the discrete GPU inside it redundant - but i have to have it to get 32 GB of RAM).
The upgrade to an i7 is criminally expensive and in the days of m.2 SSDs this should be upgrade-able via a slot like the RAM (which is also criminally expensive - yes i know RAM is expensive right now but all the more reason to have user upgrade-ability on this class of machine).
Plus they have one tiny fan so unless you can do with a non hyperthreaded i5 the i7 not only throttles but the fan is very audible when doing any sort of work except moving around the OS.
Lets be fair the RX line is mid range and at the end of the day you cant get away from the fact its a 5k display 14mp. If you do anything that is render intensive even photo editing PS/lightroom every time you make an adjustment or want to move around the image the machine is trying to refresh at 60FPS at 14mp.... LAGGY AS HELL!
Nothing runs smooth on it at all because of that resolution. You have to decrease previews by half to get a smooth experience so whats the point in having all the pixels?
Thats our only option currently, there are no headless macs. Unless you buy it and add a second lower res screen and set it to the primary. If your happy about that going in... It should be perfect out of the box.
Unless you want to pay the same for a much slower and older mac pro with no display. Then there is the iMac Pro which is overkill with it being a 9-5 machine why is it a xeon... it wont be on 24/7 rendering they just arent the right tool for that. Most will encode and guess what the xeon doesn't support quick sync. Its double the price and has the same issues even with vega. The 56 is laggy the 64 is the only card that gives an ok experience atm and its a £600 upgrade!!! Thats how much they are on their own not including the £500 vega 56 thats included in the base price!
Same with all upgrades its absolute BS that they offer the upgrades at cost on their own on top of what is already specced to the machine.
Its just unreal...
You can add external TB3 GPUs but what people forget is you need to buy a £400 enclosure on top of your inflated card! There is no out of the box nvidia support so if you want cuda its the wrong platform... Its like a premise "you can buy GPUs down the line, but dont expect us to give official support" Who knows that GPUs apple will support they are all low to mid range so if thats all you need its an expensive way to get a little more performance.
You could buy a Vega 56 for £500 or a 64 for £600 and your total is £1000 with the external GPU and you get about 90% of its performance through TB3... its beyond a joke.
Spinning drives on the 21"... and £180 on top for a 256gb ssd.. When high sierra is designed to run on SSDs. Fusion hybrid ssd/Spinning hard drives really.... in 2018... with 512gb ssds still costing £180 on top... its a joke. Its a lovely product but its an expensive product that IMO is bang average in performance, not because of the specs because 5k displays are so intensive to run.
8gbs of ram as standard... High sierra uses the majority of that before you get going, yes it can swap with the SSD and for most people they probably wont notice because they are quick. At the end of the day thats not a great solution and its no where near as fast as adequate ram... What happens when you specced the machine with a spinner... The experience is awful, how disappointed would you be? The main thing is you can still replace the ram but for how long? The mac pro removed it... so why wont the standard iMac.
Then there is the CPU options... that throttle because in the huge container that is the 27" it has one fan. The speakers take up more room than the CPU, GPU, Logic board and fan and there is about 50% more room in the chassis completely unused.
So really in 2017 the top tier imac comes with a quad i5, 128gb ssd and a 2tb spinning drive, 8gbs of ram and a RX580 for £2300 im going to remove the 5k display from the equation because to me it ruins the performance... looks a pretty expensive machine. Thats the top end off the shelf option.
The fact they sell the base line 21" that will ultimately give a sh*t experience out of the box and isnt technically compatible as spinning drives arent supported by apples APFS file system. Oh and neither are raid devices as boot drives... mind boggles
So where in this is the 2017 a great product at a great price? Non of the off the shelf iMacs offer a good out of the box experience for anyone who is interested in doing any sort of medium level work even for occasional hard work its a pain to use.
I swapped to dell workstations 3 years ago because apple dont offer anything worth having. The whole mac line is a compromise and expensive. There is nothing that looks good value because nothing is up-gradable. You end up spending more to ensure "future proofing" then in the case of the iMac you hope nothing will fails rendering it useless as the chassis is glued to the display and you cant remove failed components like a spinning hard drive... unless you pay another £350 on apple care.
With a modular machine you add as you need. The fact the mac pro is exactly the same. I loved my 2010 mac pro but it was sidelined 3 years ago because it wasn't fast enough and i upgraded it every way I could. The trash can is exactly that, trash.
So I unfortunately had to buy a dual xeon dell workstation and it minces everything I throw at it. Ive been able to upgrade it over time as and when I need. Its so nice to have an internal storage space for a raid volume it has 4 8tb drives for 36tb or 24TB of raid storage meaning I only need one external server as a back up. With any of apples products you would need another 1 external nas/raid array as a usable drive and another to back up. These are loud, kick off loads of heat and massive... hardly the minimalist desk now is it.
Add an external GPU and a TB3 SSD scratch drive and its even worce!
TBH if the iMac pro is £5k the Mac pro will probably cost similar base and go all the way up to 25k when you have been able to buy dual xeon workstations from pretty much every major vender since 2013.
The worst bit is that for most people if you use another platform then your more likely to switch your other daily drivers too... The mac built on the popularity of the pros and they would recommend to people then the event of the iPod which pulled more people in then finally the iPad and iPhone until it became what it is today.
Apple dont seem to realize the whirlwind effect that lowering mac sales/pros switching will mean to portable sales, there is only so long you can serve BS and people not wake up to the smell.
You cant just raise the price to fill that deficit like they did with the macbook pro... £500 more for a machine with less ports, no SD reader, a sh*t keyboard and a touch bar nobody asked for. If you dont want the touchbar then you have to choose a mac that has a lower watt, lower powered CPU with one fan which also overheats...
The i7 macbook is 90% the speed of the top tier i5 macbook pro 13" apart from ports whats the difference? The macbook/pro line up is also full of compromise and incredibly difficult to make a choice.
The 13" macbook pro used to be a gold standard now its in the haze of loads of great products that are cheaper and do more. The macbook pro is exactly the same as it was at conception in 2006 exactly the same use case! honestly what has changed.. apart from speed bumps. Its actually lost functionality with the amount they have taken away, SD card slots, dvd drive, display ports, USB, magsafe, F keys, functional keyboard. Its the most expensive and the least useful macbook line in its history with ridiculous flaws and non upgradability.
Every macbook and macbook pro comes with 8gbs of ram... thats only just enough now, so the market will be flooded with 8gb machines unless they were build to order. This means they will be far less useful and last far less time! Which in tern means that they will be worth less because they are less useable down the line! The mac was always a good investment and generally lasted longer than the equivalent PC but now with all the components soldier to the board the product obsolescence is much quicker than its ever been.
Ive just given up with them tbh, at the end of the day all apps are cross platform and they offer the same experience. The OS just doesn't matter as much anymore. I use a macbook for my personal use but for work... windows is the only choice that makes sense. I can tailor the hardware to my needs not what apple thinks I need and upgrade as and when, the saving over a 5-6 year period with upgrades and increased productivity... I could probably buy a full spec iMac with because I would need 2 over that period with the same issues.
At the end of the day that cost and serviceability is worth more to me than using mac os. W10 isnt perfect and can be annoying but its far better than it was. The only way I can contribute to Apple making these decisions is to not buy them. There is a lot of great products outside the apple ecosystem and its worth exploring.
Apple has opened itself up to competition and they are doing some awesome things.