Not had a problem with brightness on mine, I think its great.
Only problem I had was the set losing wireless connection and giving the message "the wireless module is not inserted" error which was a pain in the bum. I've seen a few comments online about this but not much which is surprising. Hisense tech support suggested resetting the TV which is a PITA but that only fixes it temporarily. Hisense really need to issue the firmware update to fix this. Luckily I found a workaround online.
Has anyone else had this problem?