Ask a Bowman Thread.

Speed wise? Well, there's no 'fastest' build. At 70, you make the choice between AR and Strafe. From what I've seen, AR is faster from 72~80 or so, while Strafe is faster 80~90 (After which both builds pretty much merge). With Typhons out, that may have changed, although Typhons is a VERY difficult walk.

There really is no solid answer to that question. Try checking a skill guide, and finding the particular build you like best. If you train alot, it won't matter which you choose.