Hmmm... I'm not sure if its just me, but I felt that my 4 tubes T5s seem brighter. Of course, the PAR values speak for itself, and its kinda unfair as I'm comparing my indoor tank vs an outdoor one with my eyes. I was told that the fans only kick in when it gets hot, so if your environment is pretty cool already (mine's in the office with AC ), noise from the fans shouldn't be a major issue. Sounds like regular PC fans to me.