Happs are easier to get into if you are doing a mouse hack. Imperial has a cheap 3" also which has a ps2 port.
Happs is considered the best... but many many many games come out with wico components.
note: I don't have a wico but have used them often. If they aren't right next to each other, I can't tell the difference. I've never had them next to each other to see.... but who cares.
One more note. teh 2 1/4 are MUCH cheaper (2 for the price of 1 happs 3") and the cool part... you can put pool balls (8ball, 9ball) in them. VERY nice feature.