When Apple introduced the super thin iMacs we were impressed.

But after reading Andrew Cunningham's review of a 21.5-inch iMac at Ars Technica, we're starting to think it was a mistake to make it so thin. (We saw the review via Marco Arment's site.)

Cunningham points out that an iMac just sits on your desk. If it's thin and light, there's not much of an advantage. In fact, it's problematic.

"The thing about the new iMac is that once it's on your desk, you don't often notice how thin it is. Viewed from the front, it's basically indistinguishable from the last few models," says Cunningham.

Apple's thin design still has a big bulge in the back to pack in the computer. So it doesn't save any space. Most people aren't carrying a desktop computer around, so it doesn't matter if it's light.

There is an advantage to a laptop, like the MacBook Air, being thin. It's supposed to be carried around. Making trade offs in performance for a thin laptop are worth it.

Because of the thin iMac design there is no optical drive. The speakers on the computer are pretty weak — "they're noticeably tinnier". Users can't upgrade the RAM of the computer on their own. Apple puts all the ports in the back of the machine, which is annoying. That's its design style, but if it even wanted to put them on the side, it's not an option now.

Those are all pretty small complaints. A bigger one is that Apple is actually sacrificing performance to make the computer thinner. If you walk into the Apple store and buy the standard 21.5 inch iMac, you get a "5400RPM laptop-class" hard drive, which is worse than older models that came with "7200RPM desktop-class hard drives." The older hard drive is to save space and cut down on heat.

Overall, Cunningham says he likes the iMac. But, the most interesting take away from his review is that Apple made the iMac thin for the sake of thinness, and it doesn't really do anything to improve the computer.