400R - Does anything the 500 can, for cheaper. It's replaced the Antec 900 in my $1200-$1500 builds.
Actually, the 500R doesn't make a whole lotta sense to me. Personally, I'm torn between the 400R or spending a bit extra for the Obsidian 650D, which is 162 odd on Amazon the last time I checked.
If you want to splurge, might as well go the whole hog and get the 650D, I say
EDIT: Didn't notice Whyme's post. That's why, if you truly want it, the 650D is (to me), the best mid sizer in town today, and that too by some distance. Either way, don't think you're gonna be dissatisfied, I don't think.
The 500R and 400R are priced right where they should be. You don't get the 200mm fan with the 400R, you don't get the multiple fan controller with the 400R, and as far as I know you don't get those dust filters with that case either. Both cases are great cases, and both offer good cooling, but you get what you pay for. If someone wants a bunch of little 120mm fans that sound like a bee hive...then ya go for it. But a 200mm fan runs at a slower RPM, and makes less noise not to mention less of hassle with wires running to and fro.