I had absolutely no break in on these boots whatsoever, given that they were an emergency requirement when my long time boots gave it up within days of the start of my season. Not a problem at all. Now, with about 150 hard Yosemite miles on these boots, I'm fairly pleased with both the fit and the comfort, even with an average load of 50-60 lbs. I've also had the chance to run them through about 25,000 feet of combined ascent/descent during that time. However, there are a few caveats you need to consider- first of all, throw away the factory insoles and get a pair of green superfeet. They'll help lock in your heel on the ascents and minimize the jamming on your toes during prolonged descents. Secondly, the previous reviewer was right in saying that your little toes get kind of beat up. It's not that I had problems with blisters, just that the narrow toe box tends to rub a bit on the top of the toe. I would also recommend that you wear a heavy morino wool sock and a poly liner, as the problem only became an issue when I tried to use a lighter sock. I also experienced a minor, yet notable, difference in the sizing between the left and right boots. This seemed to only occur first thing in the morning when the boots had been off my feet in the vestibule all night (rode hard- put away wet). After a couple days, I found that booting up and breaking down camp without lacing up took care of the problem within about 10 minutes or so. After that, even honking on the laces didn't give me any problems and the subsequent ankle support was great for a lighter boot. The gore tex worked well for external moisture conditions, but unfortunately, didn't breathe as well as I had hoped, hence the absolute need for poly liners. Absolutely no problems at all with sole separation, even on areas that usually indicate to me if a boot will survive or not and warrant immediate return. I suppose that whether this is the boot for you is primarily a function of how your foot is built, but so far, they do their job well enough to keep them around. I'll go ahead and give them 4 stars.