Today's CotD is Machamp Lv X, from SF. Stat-wise, the Lv X form grants Machamp 20 extra HP, increases its Weakness to
sychic: by 10 (but hey, +40 is better than X2), still adds no Resistance, and increases his Retreat Cost by :colorless (or if you use DP Machamp, it remains :colorless:colorless:colorless still), and gives Machamp a Poke-Body and new attack. The Poke-Body, No Guard, is risky but can pay off; Machamp deals an additional 60 damage (which can get you those needed OHKOs) in exchange for him taking an extra 60 damage (which isn't good). Thus, the best time to usually play Machamp Lv X is when he's fresh with full HP, so he can at least likely OHKO 2 Pokemon. To counteract the negative effects of No Guard, Machamp Lv X's attack, Strong-Willed, does 20 for :fighting::colorless:colorless (80 since we're counting his Poke-Bod) and if Machamp would be KOed next turn by damage from an attack, you can flip a coin (Heads) to save him with 10 HP left. So if you're pretty good at flipping Heads, you can theoretically keep Machamp Lv X alive forever.
Modified - 9/10 (1 is needed for every Machamp deck, and he is a good Pokemon in itself)
Limited - 8/10 (It's unlikely you'll ever play him, but if you do, he'll be unstoppable)
Unlimited - 1/10 (Since Machamp isn't played here, no reason to use the Lv X either)