I have to clarify: It's not just about guessing the password. If you do guess it, even on WPA2 you could just try logging in . Try too many times, and someone might notice. But on WPA-PSK, you can capture some traffic, and then run huge tables of passwords against it, you don't have to do any login attempts until you find the right one. And yes, WPA2 is safe against that.
Actually, while WPA2 introduced CCMP mode as a replacement for the problematic TKIP, when run with authentication based on Pre-Shared Keys (PSK), it is still vulnerable to dictionary attacks. Our service works against both WPA and WPA2 when PSK is being used.
