Well, to re-iterate what I said elsewhere:
I love the first four of his novels, though (that is, "Ashes of Eden", "The Return", "Avenger" and "Spectre"). Yes, "The Return" is the "wild" one of the bunch, as I do think the other ones are better written... But hey, "The Return" was only following one of the most vile, most God-awful movies ever (and I'm not kidding). Bringing him was necessary, IMO. And AoE is a great final chapter for Kirk and co. just before GEN, and a great epilogue to TUC.
The MU trilogy is a mixed bag... The first one is superb, "Dark Victory" is indeed meh, but still quite good - especially for its use of Garak, and as everybody knows, whatever Garak we get is better than no Garak.
"Preserver" is... Very mixed bag. Mostly because whatever role Picard has in it is abandoned in the third half of the novel and the MU focus is sorta shifted to a whole different kind of spectrum.
The Totality trilogy is OK. The first one I dug, because the first half had Kirk and Picard interacting wonderfully - their discussion about the Prime Directive is great stuff - the second half is basically a flashback to Kirk's early days and the third half has Kirk looking for Picard. THe second novel is every bit as OTT as they go - but its OK, cause its a decent follow-up to NEM, though not quite as good as the equivelant Titan novel. And "Captain Glory" is OK, but the climax and epilogue are totally awesome. Its a really fine ending to Kirk's adventures in the Prime Universe, bittersweet but also... Fun.
Never read Collision Course, and I don't think I plan to. Sorry.
Something I'd like to note: I like to view GEN, "The Return" and FC as an unofficial trilogy: The Enterprise-D crashes and Kirk dies, Kirk comes back because of the Borg's insedious alliance with a Romulan fraction to take down the Federation, and when the Federation basically closes down one
of its home planets, the Borg fight back by direct assault and then time-travel. And what links all those stories throughout is the TNG crew.