Hi Al,
Like so many of these kinds of questions, the answer is "It depends." First, it depends on how good "good enough" is for you or your client.
There are some people, whose opinions I otherwise greatly respect, who just HATE HDV of any kind - they'll tell you what you do here won't matter - it still started out as HDV. There are others who think HDV is just fantastic, when you accept and adjust to it's limitations, and when you factor in the cost savings.
If the footage you're downloading is direct - it hasn't been modified or transcoded since it was captured - that would probably be best because that data is the cleanest possible - anything that happens after will be under your control. If, on the other hand, the m2t is the output after somebody edited and then re-encoded, that's a major quality reduction. Same for quicktime files, unless they're uncompressed (doubtful for .ftp download) or ProRes 422 (also unlikely).
Here's a project I cut with one piece of cheap HDV stock footage - The "Surfer" footage I bought 'cause I didn't have time to capture it. The rest was HDV I shot myself with an FX1 and HC-3:
http://HD-VO.com/nbff ...(Yeah, I know I should have brightened the surfer footage, but it was "Good Enough" for me.)
That piece was downloaded as m2t, then converted to ProRess 422 (standard, not HQ) for editing. Big Hint: MPEG Streamclip is your friend, and it's FREE!
Travis
VoiceOver Guy and Entertainment Technology Enthusiast
[
www.VOTalent.com]