The other (and more important IMHO) difference is that, because the 4-way has a diamond-shaped restrictor, it is much easier to hit the right directions. You can actually feel the stick hitting U/D/L/R, which makes 4-way games much easier. An 8-way has just a round hole as a restrictor, so the stick doesn't "locate" as easily. 8-ways are good for fighters for this reason, so you can do all those crazy forward/back/semicircle moves. But in Pac-Man, it'll kill ya baby!!