hi,
i maybe one of the right guy to answer this,if i may say so myself.
i use my 125StreetMoto for daily commute. MPG is good. speed is just right. maintenance is easy.fresh oil every 2500km and new oil firter after two oil changes will keep it happy. check the water level in the radiator every now and then because it has no resevoir or better yet,get hi-grade coolant. i only had to reshim one of my intake valve after hitting 45,000 km.there was a slight rattle but it went away after i changed my timing chain after i clocked 50k km. i'm quite hard on the motor but it's still holding strong.
i can't help you in choosing between RT or the SM...i think it's a personal taste...
maybe you could go to a dealer and try sitting on each of them and get a feel of the riding position.
...my 2 cents worth...
p/s:the stock battery is junk. get a better one if you decide to buy the bike. good luck.