I run a Bailey four stroke, I'd say it is about the only one you will find on the 2nd hand market.
Yes it is heavier, generally comes in at around 28.5kg dry, but you generally carry less fuel so partly balances out the takeoff weight for flight.
Power output is 20-22hp (V5 V5s I believe) whereas the common Moster 185 is 25hp, the difference is noticable. If you are on the heavier side the extra is worthwhile.
Economy is the plus point at around half the consumption of a typical 2 stroke, they are a little quieter but the propellor makes the most noise.
Downside is if parts or manufacturers sevicing is required, Bailey Aviation only operates a 3 day week on Tuesday to Thursday.