The SEGA Saturn version of X-Men Vs. Street Fighter was released in Japan in 1997. It requires a 4-Meg RAM cartridge to run, and at first the only version of the game available was a box set version which included the required cart. Thanks to this cartridge, the Saturn version is an amazing port. Capcom also released a standard edition in 1998 which didn't include the RAM cart.
Everything from the arcade version is here, with next to no load times at all. All of the characters, moves and most of the animation frames -there is no contest when comparing it to the Playstation version. Probably the only disappointing aspect of the Saturn version is the lack of extras, as it only has an arcade and versus mode. It does at least have a few neat secrets to unlock, such as infinite hyper combo gauges.
The SEGA Saturn version was only released in Japan. There were talks of a European release, but it was repeatedly delayed, reportedly due to arguments between SEGA, Capcom Europe and Virgin Interactive (who published Capcom's games in Europe at the time) over the price for it. Their quarrels meant that no concrete release date was ever set, and the game was eventually cancelled. As of 2021, this is still the best console version of the game.