Originally Posted by Fat Nyara
Without TM Support: Great Mid Tier
Poliwag's best option is just remain as it's, once it evolve to Poliwhirl, just aim for the Amnesia, you're gonna do an adobe-avarage job around the game, and when Poliwhirl's stats are starting to show its problem, you're gonna get Amnesia, and that pretty much with Poliwhirl's great speed means you can sweep any trainer, gym leader, and Elite Four. I don't see any reason to evolve Poliwhirl in this case, anyway, Amnesia + High-High Speed + Perfect Coverage + Good Type is just too good to drop in favor of some physical bulk and power.
With TM Support: Good High Tier
Evolve Poliwhirl ASAP, and put it whatever TM you want, you're gonna get a TOP Pokémon until you're near of the Elite Four, were he's just mid tier.
One of the big problems with the tadpole is the level it comes at. In RB, it comes at a bogus Level 15, while in Yellow, it can range from 5-15. In terms of efficiency, this isn't where it's at. Not to mention you have to trade one for a Jynx anyway. It's Gyarados all over again, without the good points that Gyarados has (trashing endgame and monster stats).