Purchased at Best Buy yesterday for the same price as a smart cover. I got the smart cover too and was going to try both out but I'm liking the Targus case right now.
Here's what I got: http://tinyurl.com/74ggxbs
EDIT: Sorry, here's the case I actually got. Noticed the one I posted was $60 as opposed to $40 at Best Buy. Also noticed the $60 case people said they were having problems but the one I got has good reviews.
http://tinyurl.com/7a3jvpj
If you mean the sleep/wake feature, the reason some smart cover compatible cases don't work is because Apple has started using a new type of magnetic sensor switch that is sensitive to polarity. Everything is explained and demonstrated in HD video at my blog:
iPad 3 Smart Cover Sleep/Wake Feature Not Working
Mark