I own #3 and love it. I also own previous DVD's from #4 and love those as well.
Not a slight to #1 or #2, but I never saw those particular DVD's, so I am unqualified to judge. If you want to learn Vegas in a way that really teaches you how to fluently use it, the teachers on #3 and #4 are excellent. Can't go wrong with either one IMHO.
I only own #2 and found it very helpful and easy to follow and well worth the money. I got the computer version which I think results in a sharper image on a computer. The instructor has a good teaching style.
I'd migrated from many years experience with NewTek's VT NLE and had been using Vegas for about two months when I got the training DVD. I mention this to say I wasn't exactly a beginner with Vegas so it may not help a true NLE beginner get up the initial learning curve.
As to the specific recommendation, naturally, it's a matter of personal preference. Make sure to check out this FAQ page so you're comfortable with your purchasing decision in the long run.