Koryu is the best SF2CE for me, its more like a penalty shootout, each battle generally take maximum 20 seconds (not counting M Bison flying off 3 layers up, in that case its generally to run the clock out - operators hated that lol), minimum around 5 seconds and it gives a relatively unskilled player much much higher chance of beating an experienced player. Its better than official obviously and even other boots that sped the game up better.