Mawile is an ok tech card, meant to be used primarily against G&G. Statwise, he's a solid Basic, with 70 HP, +10 Weakness to Fire, -20 Resistance to Psychic, and 1 for the Retreat Cost. Pick Out is the main reason Mawile is good against G&G; it's a free attack that lets you flip one of their prizes (or yours if you want) and if it's a Supporter, lets you use its effect. As Gallade's primary attack relies on being able to flip prizes to do additional damage, Mawile can severly limit their hitting power, especially if you get it out early enough. Jaw Bite is a bit expensive at 1 Metal and 1 Colorless Energy for 20 damage, but it makes up for it by letting you do an additional 20 damage to the Defending Pokemon next turn (providing they don't switch out of course).
Modified - 7/10 (Good solid tech for the dominant G&G decks, but is weak to the other popular deck out there: Magmotar)
Limited - 7/10 (Solid card, Pick Out can be useful in snifffing out any prized Supporters as well as letting you see what you want to draw when you take a Prize)
Unlimited - 1/10 (Not much use here, is KOed too easily)