I finished the poem last night. It does have its moments. The parts in Canto 2 about worrying about your daughter, and some of the lines in Canto 3 and 4 also stood out. It really does fall apart near the end.
I appreciated these lines from the end of Canto 2:
"Out of of his lakeside shack A watchman, Father Time, all gray and bent, Emerged with his uneasy dog and went Along the reedy bank. He came too late."
and these from Canto 3:
"And I'll turn from eternity unless the melancholy and the tenderness of mortal life; the passion and the pain; the claret taillight of that dwindling plane off Hesperus; your gesture of dismay on running out of cigarettes; the way you smile at dogs; the trailer of silver slime snails leave on flagstones; this good ink, this rhyme, this index card, this rubber band which always forms, when dropped, an ampersand, are found in Heaven by newlydead stored in its strongholds through the years."
I had tried to read the book and the commentary concurrently with each other. But the commentary started very disconnected from the lines and only seemed to become more and more remote from the poem itself. The poem serving merely as a jumping off point for Kinbote to tell his own, confused, story.