FWIW I?ve rode a couple newish Beta 300?s and my Sons 22? Rieju 300. All great bikes, loved the way the Beta?s carved the twisties, but felt both needed a flywheel weight and suspension seemed harsh (could?ve been improper setup-but I?m no lightweight so there?s that.
Loved the MR 300 motor, no flywheel weight needed. Suspension was stiff as well but bike was brand new-not broken in.
Personally I?d buy a Rieju, but I?m biased as well.