I would have preferred Elizabeth Warren. I think that Hillary needed someone who would plant her standard in the ground against the mega-rich, Wall Street elitists with whom she has been so cozy. Kaine seems a convivial and articulate fellow, but his image isn't far removed from Hillary's (absent the suspicions of dishonesty.) Additionally, I think that Warren would have faithfully represented the populist aspirations of all those Democrats who supported Bernie.
I suppose that she chose him for the very reason that his integrity is unquestioned, as opposed to hers, thus "balancing" the ticket, but I think that it was a mistake.
The selection of The Donald by the Republican man-in-the-street in the primaries shows that the electorate wants someone who is an authentic voice for their concerns, rather than a plausible, plugged-in functionary. Ergo, Elizabeth Warren.
Nonetheless, I will vote for her, of course. She's not the greatest but she's not a misogynistic, racist, bigoted egomaniac. (Well, at least three out of four.)