Review here:
[url]http://www.ar15.com/forums/topic.html?b=3&f=15&t=160068[/url]

Depends on what you're looking for. FAC has the Czech ones for $299, that's the best price I've seen on a complete .22lr upper with a mag. DPMS has one that looks the same, as do a few other sources. There are quite a few other options, including the Kuehl, the KKF, the Leitner-Wise, and the option of using a Ceiner/Atchisson .22lr kit in an existing unmodified .223 upper. Depending on what you want out of it and what you want to spend, you've got a few options.
For my uses, I think I'll save up the $299 and get the Czech one from FAC (if they've truly got it in stock). It uses a right side charging handle rather than a top mounted AR type, and it comes with no optics, but I'm just looking for a cheap plinker top to put on an extra AR lower that I have, and mount an OKO sight to the flattop. I can't say that it'll be any better, more accurate, or more reliable than a $150 Ruger 10/22 that has high-capacity mags available, but it'll at least be a way to introduce new shooters to the AR platform.