Design-wise I really like the way the Tepig line and the Snivy line look. I think that Oshawott is very cute, but Samurott looks like a designer who was trying to do way to much. Mermaid tail, 4 legs, narwhal horn, samurai armor, huge body and tiny feet? It looks disproportionate and reminds me more of a Digimon than a Pokemon, especially since I feel that Pokemon are suppose to more resemble animals and natural plants.
I personally chose Tepig, mainly because of it's cuteness. So far I have been happy with that choice. I did try the other two, I thought that Snivy was to boring for my battle style and Oshawott didn't impress me that much. Eventually I will have all 3 on the same cartridge once I transfer them from my other game.