I played a lot of it in high school (1996 - 2000). Spent a ton of money on it then, in fact. We didn't worry about formats back then; we just played whatever. I remember playing people that had 5 color 300 card decks. There were random people who played in town, and my buddy used to set me up matches against them with a good chunk of money on the table. None of them were very good, but he would talk massive shit and get them to pony up money just to protect their ego (he took 20% for doing this). It was probably the most fun I'd ever had playing a game.
I quit sometime after high school when I met my soon-to-be ex-wife. I dumped all my cards for next to nothing, which I still kick myself about. I also played the Microprose games in high school, and sporadically after I quit. I got back into it when I decided to go back to college, and all the kids were playing it. They also played a loose format with anything goes. Some kids played draw 2, play 2 (land) per turn. I remember playing old cards like Lake of the Dead, Demonic Tutor, Dark Ritual, and Counterspell and the kids saying shit like "whoa, I've never seen a Dark Ritual in person before!" I felt like an old man, explaining how Dark Rituals went into EVERY black deck, no matter what or how you were playing.
So, like any other rekindling of an old obsession, I sinked in a ton of money on old cards and built a few decks I used to play with, as well as buying a ton of new stuff to learn how to build a good current deck. I was surprised how convoluted the game got, but it was still fun. I played the Magic 2013 and Magic 2014 apps on my iPad, and bought all the Magic games on Steam. It's fucking retarded they won't put in Planeswalkers but whatever. Mikhail sent me 46 pounds(!!) of old Magic cards that were sitting around a year or two ago. I remember this, because the mailman knocked on my door and asked me if I would come out to the truck and get them.
I haven't played in almost a year. I still have all my cards. I'm not going to sell them like I did some 14 years ago. I have a bunch of decks that I made, plus a bunch of the premade ones that they sell in case somebody wants to play and all I have to do is get them out of the closet. I have MTGO and bought a bunch of cards on there, too. Lots of old ones, like I did with real cards. I haven't played that in awhile, but I don't regret buying them because I can get on whenever and they'll still be there. My only complaint is that the interface doesn't look like it tried to update past 2003. Surely, with all the money that's funneled in to WOTC, they can put some into revamping MTGO. The standalone games (Magic 2011, 2012, etc) look and play beautifully, so it can be done.