Differences between the hv30 and hv40 are the hv40 has true or native 24p not very good if your shooting skiing and things with lots of movement better for short films.
Got my hv30 in june I shoot skating and skiing and I can't see I have any problems with it. No Dropouts or Glitches and iv'e done 25 tapes. Thats the only things I don't like about the hv30 is buying tapes but you can re-use them once or twice. Make sure your computer can handle the footage from your camera. If your shooting HD with the hv30 you at least need a dual core processor and 1 gig of ram.