I rather have these Minarelli engines than many others on the market !!

"under powered", ,
the carb on their 42cc looks to be smaller than many other brands in the same size, if you want more power you can simply install a larger/higher breathing carb,,

over weight,,
heaver than some but not the heaviest !!

expensive,,
they seam to cost more than some but not as much as others,, Moto Minarelli has been manufacturing engines since the 60s or longer, I'm quite sure they are a better made engine than some costing less..