I personally prefer the OFNA Chrome Top... for several reasons:
1) Direct drive. No belts to slip, no alignment problems...
2) Single motor. Simple, less points of failure.
3) Larger size provides more stability (easier to line the buggy up and start it)
4) With a gel-cell battery it works fine for breaking in the tightest motors... no lack of power there!
Ok, it's heavy... wah-wah... go to the gym.
And DO NOT get the little all-stainless one. It's ok, but a pain to set up for various cars, doesn't hold them well and keep them lined up... belts wear... I have that one, but don't use it.