I bought these boots in preparation of a 5 day/38 mile hike in the Wyoming wilderness. I broke them in over a few miles although it really didn't seem necessary. The boots were great over all types of terrain.... rocky, flat, grass, mud. Unfortunately, the right boot began to leak slightly when walking in very wet, tall grass. The left stayed dry as a bone so I knew it was a defect. I brought the boots back to the store I bought them from (dirty and all) and they gladly replaced them, knowing Merrell guarantees their products. As is the norm, I bought a size larger then normal due to the amount of hiking I'd be doing in a short period of time. I'm giving the boots a 5 star rating even with the defect because I was so pleased with their performance and comfort when I basically lived in them for 5 days. Merrell stands by their products and I'm happy to break in my replacements and get back on the trail!