I love my Altras. I have several pair and do not run in anything else. I use Provisions for asphalt running,
Lone Peaks for loose trails and short runs,
And Olympus' for long trail runs.
Altra gives all of the advantages of barefoot running but without the pain. They are Zero Drop, meaning that they do not have a wedge sole. The area under my toes is the same thickness as the area under my heel. It is a much more natural running position. They also have a larger toe box. This allows toes to splay and be used naturally during a run.
Both conditions are beneficial to running ergonomics. My wife has had chronic knee issues for several years. A few summers ago, she ran the second half of her fourth marathon with ice packs on her knees. She put on her first pair of Altras and within a few runs her knee issues went away.
The guys at Altra are great runners who know their stuff. Brian Beckstead ran Boston last year twice. He ran the race backward before the start then ran down when everyone else did. I ran into founder Seth Wold after one of his test runs. He holds several marathon course records including a 2:22 finish at the Ogden Marathon. He was finalizing design on the new Olympus' at the time. I asked him how far he had run on the test pair. He said he had done 28 trail miles before noon and had about 20 minor changes to design onto the Olympus' before they went into production.
Here is part of the Altra story:
Bottom line is that I hated running before Altras. I love running now.