Since there seems to be some ambiguous statemens:
Meopta 2000, 2100 (illuminated) were steel tube models, Meopta 3000, 3100 (illuminated) were the contemporary aluminum tube models. Meopta MeoStar R1 is the current equivalent. I guess they're all aluminum tubes. The low light performance is in the same category as German/Austrian manufacturers for hunting purposes. Mechanical construction is adequate but not comparable, like garyb said.
Meopta MeoPro is different product series, launched primarily for US market. I've handled a few but haven't had a chance to compare in low light. Mechanical construction etc. seemed comparable to MeoStar series.