I felt the A-story / B-story narrative split in "Banner Of Heaven" made the read a little too disjointed for my taste. Just when the A story is getting good, the B story comes along and stops it dead in its tracks. Then, vice versa. Incidentally, I also found the historical narrative infinitely more fascinating than the present-day narrative. It is exceedingly hard to pull off an A/B structure when both A and B are given nearly equal weight. One of them needs to be subordinated to the other. Krakauer does the equal-weight A/B better than most, but in some ways I think it's just a fundamentally suboptimal approach.
"Into Thin Air" is a fantastic read. It's got its flaws, but they're very minor and quickly forgotten.
Krakauer tends to repeat himself. To some extent, this is necessary. For instance, because there are so many people to keep track of in the book, and because some of those people have the same names, he'll often introduce or describe them several times. That much seems forgivable, even helpful. Occasionally he'll also repeat descriptions. Everyone does it, but when he repeats particularly memorable or creative descriptive phrases, they jump out at you.
These are very minor literary lapses, of course, and I don't want to make a mountain out of them. It's a damned good book, and I should be so lucky to write something like it some day.
"Into Thin Air" is a fantastic read. It's got its flaws, but they're very minor and quickly forgotten.