Altra Instinct 1: My first experience with the Altra Instinct was from watching my wife run in them. I was trying more minimalist shoes intially, but switched to the Altras for my 2nd Marathon. I only ran in 1 pair of Instinct 1s before switching to the 1.5s.

Altra Instinct 1.5: I ran several marathons (races 2,3,4) in Altra Instinct 1.5s. I really liked the soles and zero drop platform, but I was never really happy with the construction of the uppers in the Altra Instinct 1.0 or 1.5 - they seemed to me to be prone to tearing and wear a lot faster than other shoes. So when I saw that Merrell was reintroducing its Bare Access in a completely remodeled shoe, I switched back to them.

Altra Instinct 2: Well, Merrell made a construction blunder in their Bare Access 4 - that shoe's soles wear out on me extremely quickly, so I went back to Altras. I found several great deals on Instinct 2s on eBay, and bought a couple. I found the issues with the uppers to be corrected in this model, with the shoes much more sturdy in construction. The soles are a little more padded than in the Instinct 1.5s, but everything else - the roomy toe box, the zero drop, etc - was much like I remembered. I ran Arbuckles 2 Ardmore in these, and really felt good about them. However, I wasn't able to buy more than the 2 pair, so I put one pair aside for racing.

Altra Instinct 3: This shoe has quite a bit more "toe-off" (toe-box curved upwards) and runs a bit small - I wear size 10.5 in the Instinct 2s and size 11 in Instinct 3s. The Instinct 3s are also a little narrower in the toe box than the Instinct 2. Right now, since the pair of Instinct 3s I bought are 10.5s, I'm only wearing them on low mileage days (don't want to black toe) and the jury is still out on how much I like this iteration. My gut says that they are a step back from the 2s.



Running the Duel in Altra Instinct 1.5s