I have a few clients that opted for all-in-ones for high visibility locations such as the front lobby reception desk or security guard's kiosk.
They've generally been ok. A little pricey for what you get in the tin, but that's the tariff you pay for pretty packaging. Just remember - it's a non-standard form factor. So any hardware maintenance you may someday need to do will be a headache at best - or a depot repair at worst. So far I haven't had to crack one of these puppies open to do anything. But I dread the day when I might.
Asus has been a reliable brand in my experience. Better than some Dell models and no argument about it. I've also had good luck with eMachines/Gateway and Acer
- which is my current preference if you're on a tight budget.
When my GF went shopping for a new machine, (actually, she only went out to pick up a copy of Windows 7 to upgrade her XP machine) she looked at the all-in-ones and desktops while she was there. She came home with an "on sale" Acer 17" laptop with
Windows 7 installed. The price she got was exceptionally good so it was a very cost effective decision. As she described it: I think I bought a copy of the "new Windows" and they threw in this i3 laptop for a hundred bucks. (Now you know why we always have her
do the shopping when we need a new car!)
She doesn't take her new toy anywhere. It's permanently enshrined on her desk. She refers to it as her "rolltop" PC. As far as she's concerned, the lid is like the rolltop on a desk. It keeps things neat and out of sight (she hates cables with a passion bordering on mania) - plus
she no longer has to dust her screen or keyboard every so often. (Big big big
plus that part!)
Before I'd go with a unibox I'd definitely think about getting her a big screen laptop instead. They're cheaper and more powerful so you get a much better 'bang for the buck' ratio. And you're no worse off hassle-wise than you'd be with an all-in-one if something inside it breaks.
Plus, the ladies (most from my observations anyway) seem to prefer laptops over desktop PCs. Take that with a dram of whiskey however. Because no two (ladies or computers) are ever exactly alike.