I'm trudging through Vanguard: Harbinger right now. I had to put it aside, about a third of the way through and reread a couple of other Trek books that I really enjoy.
I'm back at it now and still not finding why so many people liked it. I can't like any book with the following line in it: "An acrid, musky odor clung to him like a bad reputation". Probably the all-time worst line in a Trek novel and I can't imagine a professional author writing that in a novel published anytime after the 1940's. I had to reread it three times to make sure I was seeing it correctly.