Be aware though that 500s has some known network problems:
perfect recording of high bitrate transmissions is nearly impossible
to obtain. DMM say they will eventually fix the problem, but they
haven't yet (at least, not that I know about) , and it's really an old-time
issue.
I have a 5620S and it has the same problem: I finally got good recordings
with the neutrino image, ggrab, display off during recording. But I can
only grab 1 video and 1 audio, and I don't even think about getting the
whole stream.
Music recording is ok though, I can get TS files with multiple audio tracks
at once with no problems at all.
Moreover, with a 7000 and USB, you can have multiple images and multiboot without having to flash every time you want to change.
But, 500 is a much cheaper receiver, you can have 2 and still pay less than
what you would pay for a 7000 and experiment with network settings and
cardsharing... ;-)