I've had my Nepals for the last three years and can't say enough about them. They fit my feet like a glove, have just the right amount of insulation for all but the worst Sierra winters, and my feet feel like a million bucks after a long day in them.
There was a break in period for me of maybe 30 miles or so and I did get hot spots on my heels at first - I wear custom orthotics (the 2/3 length type) that affected the way my heels fit in the boot. After changing around and trying different insole and sock combinations I found the recipe that worked for me. During the "break in" period I installed the extra tongue in the boot which did help to keep my heels locked in place better and have since taken it out.
Choosing the correct size was the most frustrating part of the process for me. The European sizing system didn't seem to lend itself to an abundance of clarity but after much consideration, I went with the 45.5 which was "about" a half size bigger than my street shoe size of 11.5 to allow for thicker socks and higher volume needed for my orthotics. It was pretty much a well researched guess but it worked out fine for me and even helped me choose the best size (46) for a pair of LS Baruntse that I got a year later for my winter doubles (a great, super warm and comfy boot BTW!).
I strongly recommend chucking the factory insoles, which I have found in most boots, is lacking in support and cushion. Be prepared to try out different styles and sock combinations in order to find out the best for you. Be aware that thicker insoles will take up more volume in the boot and can influence the fit/tightness in the toe and proper heel fit. When the boots first arrived, the first task was to put on my thick socks, insert my orthotics, install the extra tongues, tighten up the laces, and stand on a 30 degree decline (a two by four is what I used). Your toes shouldn't touch to front of the boot and there should be maybe tight fingers gap in the heel portion at the back.
Lastly, it was really important for me to be patient and sometimes creative to get the sock/insole combo dialed in but these boots are an investment in your feet and should last a long long time, maybe a lifetime. I can honestly say these boots are the best I've owned and consider them my "old friends".
