[fnsnet]

Back in 2001 competition my School Team (616) had Rack and pinion steering. It worked well (though we bought a trillion limit switches).
As a few other's have posted, the turning radius is what kills you. If you're off track at all (read: pulling into a parking space all jacked up), you almost always have to backup and try again. Building and programming the system was awesome though (back when we programmed in P-Basic.)

Perhaps when the fields get a little larger, and traveling around the (larger) field has more importance in the game, rack and pinion steering will come to the forefront. Right now though, manuverability is what's important.

Matt