[Josh Hambright]

I've used the mechanical ones and experimented with the optical ones, both seem to work well, it just depends i guesse on your personal opinion and what you have to work with (money, supplies, space, etc)
I'd say that if you want to try and build your own, go for it, but make sure you have it working now and can translate it to a robot in the build season, i'd also recommend if your going to try and buy something to experiment with it now rather then later, because when we first started integrating alot of sensors into our robots for autonomous, it was trial by fire as we went along and alot of stuff didn't work out.