I'm running mine on a CoolerMaster as well. While many people consider it to be an 'ok-ish' brand, I haven't faced any issues till date (touchwood!). Corsair, Antec are some of the better brands which will be recommended by many here over CoolerMaster.
Personally, I'm happy with a CoolerMaster.
What brand/model is your current 550W PSU? It should be sufficient for a GTX670 as long as it has a decent Amp rating.