First of all, this is a GREAT shoe! For anyone doing CrossFit or HIIT workouts, these shoes are great. Lifting is also amazing in these. The grip on the outside sole is great as well. However, with good comes bad.....for some people. If you have very wide feet or just like more room in the toe box area, these are fantastic. I have narrow feet, and flatter arches. For me, these did not work.In regards to sizing, size down 1/2. I usually wear a 8.5 in Nike's but I got a 8 in the Nano 9's. With that being said, you may also add an insert. I did this and the shoes worked great, but it made the shoe almost too small. I like a good 1/2" between my big toe and the end of the shoe. If I had gone to a 8.5, it would have been too big. Check out the sizing chart carefully before purchasing.Unfortunately the toe box was still too wide. I also have tibial shin splints and plantar fasciitis. I was really hoping that these would work, but they did not. I loved everything about them. The color, the fabric on the outsole of the shoes, but that darn toe box just wouldn't work for me. Also, I noticed how much room at the top of my foot there was. WAY too much room there, which is why I used an insert. It did help, but unfortunately made the shoe a lot heavier. I would recommend these any day over Nike Metcons. Nike Metcons are great for straight up lifting because the heel is so hard it digs into the floor well. The stability of the Metcons are great for that. But the Metcons have a tendency to cause shin splints and plantar fasciitis. So keep that in mind. I found that out the hard way.Rumors I have heard are that the Nano 8's work a little better for narrower feet.So in conclusion, if you are doing straight lifting but have narrower feet, I'd get the Metcons (just be sure to get an insert for those HIIT days). If you're combining a lot of interval training and weights, Nano's are your best bet (just be sure to get an insert if you have more narrow feet). Or if you're like me and need a good shoe for lifting, HIIT, cardio, and something to help with shin splints and plantar fasciitis problems, get the Inov8 F-Lite 235 V3. Just know that if you do get the Inov8, don't plan to lift anything heavier than 500lbs. If you're going to lift that much, invest in a pair of power lifting shoes. I got my Reebok Power Lifters for $50 here on Amazon.