I don't really ever see this manga being discussed here, but I just finished it and had a mixed reaction to the ending. I feel like by the final volume Buntarou had made his choice and embraced his loneliness, so the last few pages with him surviving felt kind of like a cheap way out of it. Even if he suffered a "punishment" by having his body deformed he still achieved his goal and is able to continue climbing smaller mountains, seems too much like a happy ending he did not deserve.
Lots of people have read it and it gets pages posted all the time. You just don't see very many threads about it.
My opinion, was that it progressively got less and less interesting. The ending was pretty cliche shit and the whole fact that he somehow got a woman to return to felt pretty forced. For a guy so thrust into his own isolation, it felt very wrong.
The author certainly didn't know what to do with some of the characters. Appeared and disappeared as they were convenient.
I read it recently as well. Great manga, but I really disliked the ending. I wouldn't say he "embraced his lonliness" - he made the decision that he valued his family and friends over the mountain, but then there was a series of coincidences that forced him to climb the mountain (and survive). There was no sacrifice in his decision - he should have either had to give up his attachments to other people (perhaps die alone but happy on the top of the mountain) or to abandon his dream of climbing the mountain. I wonder if it was a last-minute decision to change the ending from the person that inspired the story.
The parts of him struggling with people/society as a loner were great, as were the actual mountain climbing parts - the psychology of the main character was fascinating.
He died in the original novel I guess. The manga even says this?
I too hated that megane succubus character and thus the ending. Why was he so hesitant to bone the ex-manager woman who turned into a hooker but then this one comes around and he is fine with it? I loved this series, the symbolism with his desire to be in control and alone with the mountains was powerful. The whole manga besides the end and the very beginning was about the pinnacle of the medium.
And pretty much everyone on /a/ (with taste) has already read this manga, /a/ does not discuss non-active series often.