I have always felt that WH2 was the best. It improved & expanded on WH1 better then any other sequel at the time. It added 6 new characters to the roster, as well as the same character versus same character feature. Also put in all new backgrounds, added a new boss character, all new endings, and a bad ass introduction. While Jet & Perfect added a few things, they took step backwards by also taking things away. Most notably they changed the single player story mode which was intended to hype up the tournament, but I felt it missed the mark & they totally ruined the versus mode because for some odd reason your stuck with the same music & background over & over again. It gets annoying quick.
Even after buying Jet, my friends & I would always reach for WH2 on my shelf whenever we wanted to get some World Heroes matches on. Jet just collected dust on the shelf.