I have tried 4. ... e6 against the Panov Botvinnik quite a few times in blitz game and it does tend to end up with a position I'm happy with. However the statistics on 365chess.com suggest that White wins about 50% of the games and Black only 25%. The numbers are much closer with 4. ... Nf6
In my game - I was quite surprised by 6. h3 but it has been played before and I think I can see the reasoning behind it: Black has one obvious square to develop his light-squared bishop, namely g4 (probably after Nf3 by White). He can also play the more surprising Be6 in some lines, but this is generally only good if White has played Bg5, meaning an immediate Ng5 isn't possible. I believe the idea behind 6. h3 is that White intends to prevent Bg4 and then discourage Be6 by not playing Bg5. Of course Black can always leave his bishop on c8, which is better than you might think.
Whilst I welcome all comments, I'm afraid that I can't take seriously sundown316's statement that the Panov Botvinnik attack is "an over-rated piece of rubbish". This is an opening that has been used to defeat the likes of Euwe, Botvinnik and Karpov! Like almost every opening and defence which has earned a name, it is certainly playable at my level (my opponent in the game I posted is ~1900 FIDE and I'm ~2100)
Anyway, I'd like to end with this game, which I found amusing for various reasons: