I don't really think which type you learn on makes much difference if you're going commercial and converting to other types afterwards. Most of my hours are in the R22, but I've flown the Schweizer and the Bell 47 (though not the Enstrom) and while they do differ, to a certain extent a helicopter is a helicopter is a helicopter. Far, far more important is that you like the school and the instructor - visit all three, ask pertinent questions, and see what you think. Also consider if money is relevant here - as has been said, the R22 is much cheaper. Also, what will you be doing to hour build when you get your CPL? If you're at all likely to be instructing, most schools use the R22. OTOH, there are quite a few schools using the the Schweizer for training now, and less people qualified to instruct on it. So really, you pays your money and....etc etc.
Can I echo what has been said about Rotorheads. I've had so much help from people on there, people with thousands upon thousands of flying hours. The flamers are in a minority - unfortunately a rather noisy one. Still, it's nice to see helicopter related questions on here too.
Take care, and let us know what you do.