I've long added sprints to my routine walks, but recently began distance running, training for a 10K, then a 10-miler and eventually a half-marathon. I also have tough foot needs: I need a little stability to counter some over-pronation, but not too much or I start over-suppinating. I also have extremely flexible arches, though not very high, crazy-high insteps and super narrow heels. After trying Brooks Adrenaline (too heavy and too much stability), Mizuno Enigma (too narrow through mid-foot), and Mizuno Creation (not enough stability and too much arch - led to a knee injury), I was convinced to try Asics again in teh Phoenix 4 model. It truly seemed to hit all of my needs fresh from the box! Wide enough toe box, just-enough arch, lots of cushion, and stability without pushing my feet outward. I'd love the heel to be a smidge tighter, but with thick socks (which i prefer anyway), and using the top lace holes, it's good enough. Against all rules, I wore them for a 5K 2 days after getting them... and finished without pain and with a great pace! Bonus: Asics managed to put a fun color option in the Phoenix 4, FINALLY :) Fit: I normally wear a 6 or 6.5 in dress shoes and a 7 in running shoes; the 7 in these is just right.