I have and listened repeatedly to the Roth era albums, so I'll stick to those:
1. Fair Warning
2. VH I
3. Diver Down (my first VH so it sets higher for me here than most)
4. 1984
5. Women and Children
6. VH II
Really, I like all of them and still occasionally listen to them while working out or similar.
I got 5150 when it came out and liked it just fine, but I was getting into heavier stuff then and so just never connected with it as deeply, and never listened much to the others besides what was on radio or MTV. I was a fan of Sammy pre-VH, and enjoyed some of his post-VH CD's quite a bit. I should revisit the VH era albums and see what I think.
I suspect a lot of this is our ages. For me Roth era was a much more formative for me and so I have stronger emotional ties to all things of that era - but especially music. By the time the Van Hagar stuff was coming out, I was playing in active bands, had a stronger sense of identity and was far more cynical about everything. It was much harder to win me over by that point.