UPDATE: so regretfully I have to remove a star, I have two pair and the fir is amazing. However the durability is not cutting it. One pair the upper fabric near the toe blew up and the other the tread is falling apart. This is the first pair of Altras I haven't totally been impressed with the durability. I still gave them 4 stars because the last 9 months on them have been awesome.
I have had these for over 6 months now I liked them so much I ordered a second pair. Though they might not be true to size they still crush trails. Sandy trails in Zions National Park no problem, technical trails of upper Little Cottonwood no biggie, longer days like a 20 mile run that's the Superior 2's bread & butter. Only down side I can find is the sizing, just order a couple sizes (0.5 & 1 size) bigger than you normally wear and send back what doesn't work. That's why backcountry.com is the best in the biz! I normally wear an 8.5 but settled on a 9.5 and have never second guessed my decision because they have performed so well. Other shoes I like are the Salomon Sense, the Altra Lone Peak 1.5, the first & second PureGrit.