inefekt -- First, "Aren't the 1080p 3D projectors 60hz though?", the answer is No. Most films are shot at 24fps (= 24Hz frame rate = default Blu-Ray coding). Most PJs double this to 48Hz and smoother dispaly occurs if a higher multiple is used. Since the USA has 60Hz power, an even higher display frequency may be used. Acer has the best performance, for 3D, when using a 120Hz (5x the 24Hz frame rate) display rate.
Secondly, the Passive system requires a special "Silver" screen, which is an added expense (which has "hotspots" for 2D movies). Using a <$1000 PJ plus several hundred for glasses, and a normal screen, seems to be a lot less money than a $10K+ PJ plus a special screen. Which is more economical? I'll take the lower cost option every time, thank you.