Season 5 was my first full season and it was a good one...some of the guys' chants got to be a bit much after a while "Pride on 3, pride on 3" and sometimes they ganged up against the women but it was still a good season. (I felt kind of sorry for Paul who was obviously still hung up on his ex-wife, Kelly, and I felt she just needed a fat partner for the show.)
Six was probably the worst. Bob had the husbands/wives while Jillian had parents/children. A couple of nasty youknowwhats
on that one, mucho gameplay, and a generous amount of whining, too.
Seven I really liked also. It was a very long season, the longest up to that point (I think this last one may have been a bit longer?). It had its low points and outbursts and manipulations, too, but, overall, it was pretty good.
Eight was good, too, I thought. That one was themed "Second Chances", so there were some heartbreaking stories on that.
I just checked Hulu and they don't have seasons 2,3,4. And you have to pay for it if you want to see entire episodes.