I've had the Altra Instincts since early April, and they've become my go-to shoe for distance.
I've got 350 miles on them now (okay, 343 miles, but that's close enough), and it's been long enough that they've shown their long legs. I've rotated them with the Saucony Kinvara (now retired), the Merrell Trail Glove, and very recently the Skechers GoRun.
I surprised myself, as well as breaking every common-sense running rule, by taking them out on a 10-miler on my first wearing. My longest run in several years. Yes, they felt that good. And still today, they're the shoes that have the most toe room of any I own (including the TG).
Toe room has become THE yardstick by which I measure running shoes. Even shoes advertised as having a wider, roomier toe box have fallen far short of the better shape needed for real toe splay. The ball of the foot (where they seem to want to measure foot width via the Brannick device) is only one measure. And most shoes start tapering inward as soon as they pass the ball, squeezing the toes together. When I look at my weighted bare foot, my big toe goes out in a straight line from heel to ball to toe. It would seem that all these companies think the world suffers from bunions!
In any case, the Altra Instincts are, so far, the only running shoe I've tried on that truly solves that issue. My toes have full freedom in them.
[ NOTE: The only clean-up I did on these shoes was to scrape the dirt off the soles, as I'm getting ready to take them on a trip to Chicago.]
These shoes have worn very well. As you can see from this first photo, the uppers are showing little, if any, signs of wear. I've re-tied my shoes, tying a knot to isolate the lower eyelets (where I keep very little tension) from the upper eyelets (which keep the shoe on my foot just fine). I have always worn socks in these shoes. One time I wore socks that were short, sush that the top fell into the collar -- by the time the run was finished, I had a bloody spot on the back of my heel. The collar material is not so barefoot-friendly. However, it is robust.
I was initially concerned with the logevity of the sole. I've had issues with non-carbon-black soles wearing out quickly. I'm glad to say that is not the case with the Instincts. This photo of the bottom shows very little wear, and even that is only on, what is for me, the initial contact point of the shoe to the ground. In fairness, much of my running is offroad. My long runs are about 3/4 pavement (concrete and asphalt), so it's not like I've been doing all those miles on soft dirt and grass.
The insoles give a good idea of the amount of compression-set in the midsole. This is usually one of the weak points of any running shoe, where the balance is made between cushioning, weight, and endurance. Less give usually means longer life. I don't know what Altra uses for their midsoles, but it's holding up very well. I don't think I've had any other running shoe of this weight last as well. And many that were heavier in their midsole haven't lasted this long at all.
How long will they last? I have no idea, but they're not going to give up any time soon. Altra is an upstart company with a sound philosophy that has a hit on their hands, and I'd love to see them get a good foothold (haha) in the market.