There is one poster that points out all the issues with the All in one iMacs. I agree and don't agree.
I agree that there is a huge gap between a Mini and Mac Pro. iMacs are a great all in one. They last forever. I still have an old G5 one that has not been shut off since it was bought and runs just fine... it's over 5 years old. It's no speed demon compared to the newer macs in the house... but no 5 year old computer is fast by todays standards.
As for worrying about the screen going bad???? I got better things to worry about. I just don't see that as a huge issue because it rarely happens.
As an IT pro who handles laptops (HUNDREDS of laptops, not just a few.)... LCD screens do go out. They can develop color lines, or dead lines, pressure marks that create light spots, or dark spots, backlights fail... although CCFL may be worse at that than LED, and sometimes the signal scrambles, either at the video card end, or at the display rendering end, in the LCD assembly.
I deal with laptops, but my family has iMacs. My father had nothing but trouble, and finally after a power supply, and a hard drive replacement... the third time, the screen went out, on a 20" Aluminum, and he had to buy a full newer iMac... not just a new monitor, or a new CPU with an existing monitor. It isn't beyond the realm of do-able, but it is spending more than is really comfortable, when motivated by component failure on the previous machine.
My mother in law has an old half-sphere with the articulated flat screen monitor type iMac, and it is running great, albeit showing it's age. But her previous eMac blew a capacitor in the video section of the motherboard. Instant toast. If it had been a CRT monitor, the main CPU could have still worked, and just needed a replacement monitor.
Conversely, if the main logic board of any of the iMacs or eMacs would have gone out, you instantly have a monitor built onto a dead computer, that you can't use on any other computer.
Computers and monitors don't fail at the same rates, and don't go obsolete at the same rates, either.
Obviously, I don't have THAT big of a problem with AIO computers... that I suggest them to my family members. But if there were a choice for a mini tower form factor, with a separate monitor, I wouldn't have to procure whole new systems for them, when they break, and I could have mixed and matched working components, for lower costs, for people like my mother in law who doesn't need a lot of power, and doesn't want to spend much.
However, if an AIO were inexpensive... She could use an AIO machine made out of an iPad's hardware specs, if it were cheap enough, free standing or dock-able to a stand, and big enough for her to see it nice and big with settings-variable resolution or variable icon and text rendering, and a keyboard that she is used to typing on, and with enough OS power to be stand-alone, instead of subservient to a master computer running a full OS for updates and backups.
It might even be easier yet for her to use by touch, than when I had to teach her the concepts of click and drag, from her hand on the desk to the arrow on the screen, or that closing a window doesn't close an application. The sorts of things that teaching a non-computer-literate person involves. New concepts. Touching what you want on the screen is an easier concept to first learn.
But if it fails, again, it had better be cheap enough for me to just get her another one, without breaking her or my budget. Big-gift-able price. Not new iMac price.
Apple needs more versatility in their computer lineup. Choices between mobile, modular, and AIO from 500$ to 2000$. Above 2 Grand, it gets pretty traditional into full towers, and powerful mobile workstation laptops, and maybe a high-end AIO like a big, optioned-up iMac.