I have built several 2 stroke Chinagirl MB's and two 4 stroke, 49 cc HS and 99 cc Predator MB's.
Once you drive 4 stroke MB's, you will have much less desire to drive the 2 stroke ones.
The throaty sound, the low end torque, the way better fuel economy, the lost hassle of mixing fuel, the reliability and longivity, tha lack of stinky exhaust, are all reasons that make me like the current 4 stroke MB engines better than the Chinagirls.
Yes, the Chinagirls are closer to plug and play as far as installing, but I find the extra effort required for the 4 strokes well worth the investment of a little more time and money.