After many years of flailing around on a bunch of 26" rides, I'm going to take the plunge and splurge on a 29er. I have an Ellsworth Joker set up for light duty AM riding and an old K2 4000. I'm 6'4 with a longer torso than inseam and was wondering if you guys had a recommendation on whether I would do better on a Surly Karate Monkey or a Niner S.I.R. 9. Thoughts?