The Boulder X was my second choice for an approach shoe. I initially bought 5.10 Guide Tennies, but the first pair was too big and when I went down a half size they were too small. So I jumped brands. I ordered both the Boulder X and the Mix (also La Sportiva). I was really impressed with the fit of both shoes (having European half sizes basically gives them American quarter sizes). The heel was snug and I had no slippage (something lacking in the 5.10s). The Boulder X has a lace around the heel that really snugs things up.<br /><br />My overall impression of the Boulder X was that it was rugged. It has a nice looking edging zone at the front of the toe. The lugs were nobby and looked like they would be good for hiking. There is a lot of lacing, which is both good and bad since they are a pain to get on and off but there is a lot of customization to fitting. The rubber seemed pretty sticky, picking up plenty of dog hair as I tested them out around the house. They definitely look and feel more like a hiking shoe than a climbing shoe. They are a lot stiffer and have a lot more support than a climbing shoe or more minimalist approach shoe. Just testing them out in the house I noticed they were quite warm<br /><br />While I liked the Boulder X I did end up sending them back in favor of the Mix. The Mix is much lighter and more flexible. The rubber seemed softer and stickier. The trade off is in support and durability. I feel like the Boulder would probably last longer and perform better on longer hikes. But currently most of our approaches are less than an hour, so I opted for the more comfortable of the two shoes. But if I find myself doing longer approaches the Boulder X is top on my list.