I'm contemplating selling my 3 vx2100's and upgrading to Sony HDR-sr7 or sr8 camcorders. I know they look small and consumerish, but I'm wondering if they give better quality due to their CMOS sensors and higher deffinition especially in low light scenes. Does anyone have experience with these cameras?

Peace, Rolland

The vx2100 is in a class of it's own when it comes to filming in low light conditions, the hdr series will not perform as good and you will require a stronger lightsource.
If you are planning to downconvert your footage to sd to burn on a regular dvd the image quality should be comparable, only during dark scenes were it's not recommended to use strong light the vx2100 can't be beat.
When you burn the hd footage from the hdr on a blue ray disk that will look significantly better on a big screen then what the vx can produce.

I also think the camera's are too small for semi pro or proffesional work, have you ever tried keeping such a small cam steady in a handheld shot? In that case a vx size camera is a much better option (Not as good as a sholdermount camera but close)

Not only that, but the SR series are AVCHD based camcorders, which currently aren't easy to edit by most of the major NLEs. You'd probably want to look into HDV tape based cameras.