They are very good bikes. The jetting can be lean if your running 40 or 33:1 on the main jet. If you do run those oil ratios the bikes like a big main jet. 185 standard but as big as a 210 is needed in the heavy going. The needle clip like any small bore needs changed every day your out if the weather has changed.
If your a fairly quick rider I would check the rings every 10 hours and a piston change every 20. If you are fast fast every 5 and 10. Bottom end checked every piston change and once a year get the mains and big end done regardless.
Gearing wise I think they are a little long and need a tooth up on the rear.
Suspension I am not sure how the spring rates compare to the older 150's due to the linkage and valving changes this year. But I imagine they will be soft ish and set for a 9.5 to 10.5 stone rider.
You hear a ton of horror stories but to be honest (I am debating between a 150 or 250 sx 2012 for my next new bike). I know of 5 riders with them and I have helped them a wee bit in maintenance engine & suspension schedule etc and none have failed. Those guys range from back of the pack c rider to a fast a rider and they are used twice a week in general hard going conditions due to the lovely Scottish weather.