Too bad that the YS is the only 4 stroke that has that kind of transition and power. I personally switched from 4 strokes over to 2 strokes in my profiles/3D type planes and have not regretted it. If you can afford the YS and do not mind having to send them into the shop for service/paying for at least 20% nitro fuel, then by all means buy the YS. For me the 2 strokes are just a little easier to deal with.

BTW, how many Webra 50s do you see for sell on ebay? Not too many compared to some brands of 4 strokes. Things that make you go hmmmm.