Yugioh is too complicated for me by far. Also, MTG doesn't appeal to me, and besides that, I don't like Vanguard. I might pick up some Pokemon boosters if/when I get the chance in a few days, more out of curiosity then anything. Yeah, hearing about how cheap it is to get a competitive deck for it as well makes me reconsider it perhaps a small bit as well.
I never was into the card game, because I've never known anyone who played it, but I used to collect the cards as a kid (stuff from the first few original sets). I did play the TCG game on the GBC, though, which was pretty fun.
I remember trying out the TCG Online a few years ago, kind of short after it released, but it didn't really manage to hold my interest and I quit playing after a day or two.
But last month I decided to give the TCGO another try (was getting a bit bored of Hearthstone), and I'm really liking it now. There's a good collection of cards available, easy to play against other people and the community is pretty good (except for the greedy traders looking to rip off any and every one who isn't aware of the exact prices of cards). With the recent update it's become really easy for new players to get more cards fast and get a way into the trading scene without having to spend real money on packs/codes.
The only thing I'm not really fond of with the Pokémon TCG is the strange decision of getting rid of the concept of evolution with EX cards. I don't really understand why they would do that. Why should people be able to play a Venusaur EX right off the bat when a regular Venusaur needs to evolve from Bulbasaur and Ivysaur, and on top of that it gets more HP and more powerful moves than a regular Venusaur too!? Then there's your legendary EXes, because plain legendaries apparently aren't powerful enough (they are, though), I just don't get it.
But oh well, I just love making decks around the Pokémon I like. It's got that edge over Yu-Gi-Oh for me, which I do like, but it just doesn't beat the feeling of building a Pokémon party and play with your favourites.