After 2500km with my discover 125 st its a pleasure to tell you guys bike goes like a horse , for people who complaint about vibration what I came across so far is in the fifth gear until you pass 55 km mark there is a slight vibration and after that margin it goes away, as I recently passed the run in period still the maximum speed is 85km/h and it was smooth, does 60-64 km /L depending on how you ride the bike.
I had a Bajaj major 80 and a iPlatina 125 and satisfied with this new purchase, I have ridden this bike continuously for 100+ kms between the speed of 40-45 and there were no problems even with engine heating up. Hope this helps. Live free ride hard!