The hf s10/s11 has a better codec (MPEG4-AVC / H.264) than the hv 40's (mpeg2), longer record time, and more megapixals which I would prefer for event videography/ weddings as a backup cam, the one thing I wish the hf s10/s11 had was the native 24p. I have to say that both cams are amazing.
yes im a little at odds here........one hand hv40 is easier to edit, better in low light and the 24p.........but then im told the s100/10 is better quality image and of course the whole memory arguement......hmmmmmm.
I like my HFS100 much better than my Hv30, but I was never too fond of tape. I do image the native 24p is nice, but frankly I don't think removing pulldown is too hard.
I also don't think the low-light difference is big, and I like the way we can control gain on an HFs100.
My vote is the HF S10. I prefer AVCHD to DV. Not to mention the HF S10 has a bigger sensor and 3 times the megapixel resolution. The video it shoots is pretty jaw dropping for a $1k prosumer cam. It rivals most semi-pro cams. The one and only advantage the HV40 has is that it shoots true 24p, but I dont think that would be enough for me to choose it over the S10.