i've got a 35 but yet to take it to any decent trail centres. have ridden a fair bit of quick singletrack on it and it stood up to it well, its very light so you can throw it around well and relly good for climbing. recently cycled the south downs way and purbeck hills on it and the bike didn't miss a beat so i'm confident its a good trail machine and i love it the more i ride it.

batteries can do funny things and let you down intermittently. 5 years is not a bad life for a car battery. i would start by getting it checked. other possibilities could be faulty starter motor, bad earth connection to engine, starter relay or ignition switch. i would guess most likely battery

30,000 miles is not bad at all for a set of pads