As well as i noticed that Qihoo heuristic catches more than signature. I had been seen a lot of MT malware samples been detected by Qihoo as QVM something something than numbers at the end of it.No, Q360 TS own database is updated very often and does not lag behind. Avira usually does update timely, too. BD is kinda problem. Sometimes, it lags behind for one day. In most cases, I need to manually update 3-4 times to get the new signatures (sure they might come by auto-update too). I manually update as soon as I start the PC, it's kinda habit I had with every AV I had.
According to VT + this forum, I noticed that Qihoo's Signatures a pretty strong, and they're cloud based.