I've played pokemon, wow and magic. I never got into yugioh. It just looked messy.
Pokemon - simple, but couldn't find anyone to play with. I had a pretty good deck. Electabuzz was a beast. 70hp basic, 1st attack 1 energy that might paralyze and a 2nd attack that cost 2 energy that had the potential to do 40 damage... yea he was badass.
Wow - has a great resource system so that you NEVER get land screwed like in MTG. However, the game favors rush WAY to fast. One thing is that there are buch of 2/1s, which in magic is a RARE. Secondly, each attacker can hit whoever they want to, either the hero (which is like the player in wow, as in 0hp = lose) or other monsters. The classes are supposed to add variety to the game, but only about 2 or 3 are actually useful.
Magic - Good game. Can get annoying with rules and such, but it's really well-made game. Only problem is the land screw. If you get 0 or 7 lands as your hand, you will be severely behind as you play. That and playing a lot of formats is expensive... So I suggest playing with theme decks or limited.