I used to own the track 2 low tops and while the soles did wear out as has been pointed out, it took 7 years so I wasn't real concerned about it. But I haven't owned a pair of Eccos for several years and have been wearing Merrils for a while.

Well, I recently developed plantar fascitis on my left footI decided to look into Eccos again and that's when I noticed the Ttrack 6 has a rubber sole and not the "manmade" sole of other track models. I'm guessing these soles are in response to the other track models with the disintegrating sole.

I have to say, they do not feel quite as cushiony as I remember the track 2's but they are extremely comfortable--AND my plantar fascitis is almost entirely gone!

I can';t attest to the longevity yet but since I think a lot of the problems are climate based and my Track 2s lasted so long I think these will last as well.