First I will state I'm a developed so I send a lot of time on my keyboard. Because of this a good and comfortable keyboard is a must. I've always found this style of Apple's keyboard to be their best. The layout just fits me perfectly.

Although that's my main complement to this keyboard it's also the most important. There really isn't much else that can be said about a keyboard. They keys are spaced perfectly apart and give good feedback when you press them down.

As everybody mentions these things collect dirt like crazy. I'm a fairly clean person and don't make a habit of eating at my work station but even my keyboard looks filthy underneath. This isn't so bad considering all keyboards get like this but the transparent plastic around the keys allows you to see the crud. I end up pulling all the keys off and cleaning it about one every two months.

The keyboard takes four AA batteries and they don't last more than a few months. Since I use rechargeable batteries I don't care about this too much but if I was feeding it disposable batteries I'd be none too happy.

But neither of this downsides outweigh the comfort of this keyboard for me so I stick with it.