The premeir draw source of this format, Claydol is used in nearly every deck out there. Stat-wise, Claydol is solid, with 80 HP, a +20 Weakness to Grass (could hurt with Leafeon Lv X threatening to be big when it is released, but Claydol is meant to stay on the bench), no Resistance, and needing 2 Energy for a Retreat Cost. Claydol's only attack, Spinning Attack, does a solid 40 damage for 1 Fighting and 1 Colorless Energy.
Claydol's Poke-Power, Cosmic Draw, is the sole reason you will usually run a 2-2 line; it allows you to put up to 2 cards in your hand to the bottom of your deck to then draw until you have 6 cards in your hand. This is great in being able to continually refresh your hand and ensure you have the best options available. Claydol is also notorious for killing Absol starts, as the lost cards matter little if you can maintain hand presence, and also helps to counteract the otherwise potentially negative effects of Team Galactic's Wager.
Modified - 10/10 (If you're not using at least a 2-2 line in your deck, you better have a good reason as to why)
Limited - 10/10 (If you can get him out, he's great in helping you shift through your deck faster to get to your key cards)
Unlimited - 1/10 (Not really worth using since there are so many other great draw options here)