Out of interest, why are you downgrading?
I'm in the market for a small, low-powered laptop and am torn between the rMBP 13" and rMB (leaning towards the latter!). I don't like the Airs. I just want something I can pick up and use as, basically, a better iPad – I'm not a fan of the linear experience of iOS for anything other than my phone.
Since I'll only be using it for Office, super basic Photoshop editing (I mean, like, resizing an image), a bit of web development, and the usual browsing/emails/etc. I think the rMB will be adequate. I need convincing it'll last a couple of years without getting sluggish/hot. I have my fully-loaded iMac for proper work.
Anyway, I'm digressing. I'd love to get some opinions from those who are ditching their rMBP for the new rMB.
I'm very much looking forward to the 10th. I'll be going for a browse at Regent St. at some point on the Friday - fortunately I work just 20 mins away.
PS. Which case did you get?
Well... I will try to not make a long post and go straight to the facts:
Current computer: Macbook Pro Retina 13 early 2013 8Gb 256 SSD - AppleCare -- Case: Be.ez rMBP13 sleeve
My usage: I'm a avid gamer, like I play every single day so I got a top of the line gaming PC and a PS4 for games. On my Mac: Movies/TV Show/Popcorn time - browsing - Office etc.
That said, if I need power to do encoding I have something else (PC), but since i'm using a computer I never encoded a DVD/BluRay and the light encoding i'm doing (converting iPhone video into a smaller footprint) was not a problem on every Mac I owned - Powerbook G3, various MB, MBA and MBP, rMBP) (I used to be an Apple Reseller

)
I also had the first rMBP 15 and at that time the quad i7 was a beast, but I never used it's power.
So knowing that what is my remaining usage? I plug my Mac sometimes on a external screen, and I almost never use thumbdrive. I have a Dropbox Pro account where I store my whole life (it's my home folder) so port is not a problem for me.
Power? The Core M will be plenty enought as I never had a power problem even when I was using a MBA!
As stated on a previous post talking about Core M perf, I tried to open 3 ultra heavy movies using wifi on my rMBP and the CPU was @20% will something like 25 programs opens. WHO NEEDS MORE POWER? (except pro who are rendering/compiling etc)
I use sometimes Photoshop and Pixelmator and I had no problem with a Macbook Air 2011 with 4gigs of ram, I'm pretty sure that I will not have any problems with a more powerful computer.
The Size and weight difference is large, and i'm pretty sure I will be as surprise as the time I opened the rMBP 15 compared to my old MBP 15.
The only thing that I will miss is that when I'm traveling, I can only take my computer adapter and recharge my iPhone + iPad plugged on the rMBP lid close, plugged to a wall outlet.
However the fact that the USB-C is a "open" port will allow battery to recharge my Mac of hopefuly use any USB socket to recharge is (even if I doubt that 500ma could recharge it, let's hope!