I'm pretty much in the same boat (although I ended on 91% completion, then came back and got 100% – two challenges are a real bitch). Really enjoyed it, looks awesome. Combat feels good for the first time in a Tomb Raider game, but I'd still prefer more tombs / temples / puzzles. When I got the achievement for "All Optional Tombs completed!" I shed a little tear, because reviews said later tombs were better and I expected a few more, but they were all short single room deals. I could also do with less semi-QTE scrambling across disintegrating bridges / burning buildings / whatever. Leave that to Uncharted.
So I've completed it, took around fifteen hours I guess. Managed 96% completion on Medium. Liked it a whole damn lot, looking forward to see what everybody else thinks of it!