Chillbill, on 21 November 2012 - 10:23 AM, said:
jeez,, it's t.h.e.r.a.p.i.st and they blocked r.a.p.i.s etc
Arrested Development joke incoming...
Anyway, I would decide based on what role you like to fill, and which mech will work best for that role. For example, if you like being a slow brawler best, the assault (presumably an atlas) will probably be your go-to. However, if you like having more speed and brawling, a heavy or medium chassis would be a better choice. It's hard to tell without knowing which mechs you have.
However, if you don't like acting as any particular role (and some would argue this is not necessary in the first place) I would just continue playing as each mech, because why limit yourself if you enjoy many different chassis and weight classes?
Another possible way to narrow down your decision would be to look at the other variants of each mech to see which ones you think you could run effectively. This isn't as important as you can also just transfer XP from your 1 or 2 favorite variants, but if you want to avoid using MC, that could be a deciding factor.