I have to say alot of people will probably disagree as the current trend is high BB bikes. Which is fantasic if you want a pogostick, but if you want to ride a mixture of actual trials (walls, logs, rocks, man-made sections etc) a lower BB bike is better. I ride a +35 at the moment which I feel is about right. A +55 is great compromise if you want a bike that is better for sidehops and feels easier on the rear wheel but can still tap (with a bit of technique adjustment).