For the same $1,299 you could spend on this 21.5-inch Apple iMac, you can buy a 23-inch or even a 27-inch Windows-based all-in-one, and with more robust features.
Apple iMac 21.5-inch (December 2012)
The Good
The Bad
The Bottom Line
Yes, for better or for worse, those other PCs have Windows 8. They also have touch screens and optical drives, features that Apple has deemed inessential for a desktop. You might agree with Apple. You might also accept Apple's hallmark design excellence and display quality as worthy substitutions. You might even need or want a particular function of OS X that you can't get in a Windows PC.
Judged purely by its hardware, however, the 21.5-inch iMac is an expensive all-in-one with less functionality than its competition. I would not recommend it to someone looking for the most computer for his or her dollar.
I don't have much to add about the design of the 21.5-inch iMac that I didn't already mention in the review of the more expensive 27-inch model.
As evidenced by the iMac's thin-seeming profile and clean appearance overall, Apple's design lead over the rest of the PC industry remains healthy. You can count me among those who felt disappointed that the new, bulge-backed iMacs were not as thin as Apple originally presented them as being. I quickly got over that disappointment after spending a few minutes with the new design.
Like the 27-inch iMac, the 21.5-inch model has a rounded protrusion on the back of the screen that houses the computing components. You will only notice the bulge when you look at the screen from the most oblique angles. You don't notice its thinness either when you're sitting directly in front of the iMac, but from most other vantage points, the screen appears as thin as its 5-millimeter edge.
That new chassis has only a cosmetic impact on the user. More functionally meaningful in theory is a new glare-resistant screen coating intended to address complaints about too much environmental reflectivity on the previous-generation iMacs.
Our lab -- all long, bright, overhead fluorescents -- is a challenging environment for glare testing. I no longer have the 27-inch iMac on hand to compare, but I know I noticed the reduced glare on the big-screen model when I reviewed it. My impression is that the 21.5-inch iMac is more reflective than the 27-inch version.
I don't have the means to objectively measure reflectivity. My impression could be due to variability in the coating between applications. It could also be a function of the absolute size of the reflected light source hitting the 21.5-inch iMac's comparably smaller viewing area. In any event, while the apparent difference is not enough to ruin the iMac's usability, if you're undecided on screen size and glare is a concern, you might head down to your local Apple Store and compare the screens yourself.