you are correct about the chip size, my typo! The cheap CMOS chips are noisy, but high grade CMOS chips are quickly replacing CCDs in even high-end digital still cameras i.e. D20, etc. The GS400 is a sweet camera, and was my number one choice before I decided to go HDV. From what I've hear, the low light performance can be very nice in the progressive mode as the sensitivity increases and noise is lowered by row-pair summation. 3CCDs have their problems, I also run a PD150, and yeah you can shoot in the dark, but the picture still looks like video (honestly in good light I am much happier with GS400 footage than the 150), the 400 can be very filmic esp. in procinema mode. The advantage of shooting in HDV that sold me is the 4:2:0 colorspace, resolution and clarity. I know the reason DV is 4:1:1, but that doesn't help me for going to DVD, AVC, or MP@HL.
yes, with prosumer HDV the sensitivity is a few stops down from DV but the end result when exported to DVD is superior IMO. Noise is much more like film grain and therefore much more tolerable and the color really pops out nicely.
That being said, I would highly suggest the original poster consider a GS400 given price range and reports the newer Pannys aren't quite the gem the 400 is.
peace, chris