I use the GY-HD100u and it produces wonderful 720p images. The sound capture also can be compressed so you don’t lose the peaks. I recommend using a hard drive that allows to record in multiple formats like quicktime, dv50, m2t, et al.
It is not good on low light situations where you have to crank up the gain above 9db. The camera system gets really big once you add a pro battery system and a matte box with rails, but the results are really sweet. Good luck.