Since its about B2/W2 I only chosen Oshawott as my starter.
[but if you must know, I used Snivy when I played White, and later traded Oshawott over from Black 2, to have both of them, back when I restarted Black 2 - after beating Elite 4]
In Black 2 I choose Oshawott because of Dewott (he/she is my #1 favorite Pokemon at the moment), and since evolving to Dewott he has not evolved at all (now is at level 61), about to take on E4 and Dewott will help out.
In White 2 its my personal "Mustelid Challenge" so Oshawott is the only choice (as sea otters are aquatic mustelids), and once again after she evolved to Dewott she now holds the everstone, at level 47 (2 more badges to go).
No issues with Samurott (its my #3 favorite), I just love Dewott more.