Not so much a rules question, but:
I seemed to have a much stronger force then my opponent who just chose Mechs and Conventional forces. A Conventional Force CHQ can take Mechs as well – no other restrictions?
Obviously, it depends a bit on what conventional forces your opponent took. But mechs really are very good. If a mech-heavy force can’t win against a force with no mechs, then someone isn’t designing or using his mechs properly.