i used both happs and x-gaming buttons in my current project. i wanted to save some money so i bought the x-gamings, once the happs buttons went on sale i decided i needed some color. the happs do have a slightly better feel, but i have no problems with the x-gaming ones. the only problem i have with them is the length. i used 3/4 inch mdf and1/8 plex for my cp. with the way they threaded the nuts, the only way i could get them to tighten was to screw them on upside down. otherwise i would have had to counter sink all the holes, and that would've sucked. it worked, and they are tight but i would have prefered to have intstalled them properly.
i know a lot of people on the board are or have used these. do a search. there are some detailed descriptions and comparisons that can be found for the joys and buttons. good luck with your game.
-chris-