This is my first pair of Asics  2170.  I have been looking for a shoe with the extra cushioning around the heel to help with my recently developed plantar fasciitis.  This shoe did the trick.  I acutally tried on the Asics 2170 "road" shoe in a store for fit and immediately like it over other shoes I had tried on.  I will say that the trail shoe has a much stiffer rigid upper portion of the shoe, I guess to help with stability and support when on uneven terrain.  It was a toss up as to whether to get the road or trail shoe.  I do walking/running on both terrains during the same session, so I opted for the trail shoe.  (Besides the price on Amazon was an incredible bargain).  To my surprise, it did give good support on very uneven grassy terrain mixed with rocks, although for serious off-road hiking, a hiking shoe with good support cannot be replaced. I am happy now to function at an almost normal level wearing this shoe with my plantar fasciitis, and even that has improved.