I've gone through a pair of Saucony Fastwitches and a pair of Mizuno Mushas. The Fastwitches just didn't feel "fast" at all, had sort of a dead feel to them, and I the Mushas were a little wide/clunky/sloppy-fitting for my liking. I wear Nike Streak LTs for track workouts but I need a little more cushioning and support for longer tempos and fartleks. Seems like a marathon flat is the way to go but not sure which shoe to try next. Any suggestions? I was thinking about trying the Nike Lunarspeed, more of a lightweight trainer than flat, but I tend to like the feel of Nike shoes.