Initially released in 1993 this card game has a lot of content, about 20,000 cards, and it is a bit overwhelming. As a rule of thumb though, the more players the longer a game will take, personally, I think a four-player game is optimal.
With the huge number of formats available it is tricky to pin down how many players the game can accommodate, that can also be said for playtime. There is a large community surrounding Magic and if you really get into it there are often tournaments held at your friendly local game shop. The original collectable card game (CCG) that can be played in numerous formats.