I've beaten the game with Samurott and almost with Emboar. I loved samurott so much! It was an amazing phsical sweeper, with an admant nature plus a "loves to fight" personality! I loved the move shell blade, it was very reliable, I just wished it had more PP.
I didn't actually like Emboar that much. First of all, it learned Arm Thrust at 17, it can't learn a good fighting move till way late in the game, either by remembering hammer arm as emboar, or by teaching brick break (obtainable late in the plot).
I'm working on the game with Snivy. I must say, I love it! It learns leaf blade, one of my favorite grass moves. I'm going with either Snivy or Oshawott, but my friend with whom I battle said she's choosing oshawott, so I'll probably go with Snivy just to have an advantage on her.
Hope this helped!