I thought it was an excellent book and it's my favorite FotJ book since Outcast. I know a lot of people liked Allies, but I found Vortex much more compelling. Ok, here we go.
Plot: Looking at it from an unbiased standpoint, it did have a lot in common with Allies. Luke and Ben team up with the Sith to find Abeloth who ends up taking the form of one of Luke's ex-girlfriends. That's pretty weak to repeat themselves like that, but I found the book to be so well written that I didn't even notice it until a couple of days after I finished it. I found it to be compelling all the way though. And I don't actually mind the slaying of all the Bantam love interests. I have always wished that they'd die in a fire, so I'm quite pleased.
Luke and Ben: They are my official favorite characters of the series. They've finally figured out how to mature Luke without making him boring or all-powerful àla the Bantam days. I also think Ben is coming into his own as a character. I still don't love him that way I loved, say, Anakin Solo, but I can see him becoming a character I can love that way. Also, he had my favorite line of the book. "
Don't worry, it's only a flesh wound. All right, a lot of flesh wounds," Loved it.
Vestara: I have never been and still am not a fan of Ben/Vestara. I'd prefer them to go another direction. But this doesn't mean that I don't like Vestara as a character or that I can't admit that they're playing out the relationship well. If they must do it, this is the right way.
Jaina and Jag: I am so relieved that they're relationship was sorta kinda resolved with a minimum of drama. I am not pleased with the complete shafting that Jaina has received lately. Do the authors not know what to do with her or something?
Han and Leia: To me, this was the best they've been written in quite some time. That is all.
Jedi Council/Kenth Hamner. Poor Kenth, At least by dying he actually contributed something to the plot. His death wasn't meaningless like other recent ones have been. *coughMaracoughIsoldercoughJacencough* I do have to say, though, that as needed as I think his death was, I was properly horrified that it's come to the Masters fighting to the death inside the Jedi Temple itself. Tsk tsk, everyone, how did it come to this kind of violence? And I don't even mind violence Ah well. Hopefully it will at least be the end of the Council bickering like younglings.
Allana and the Barabels: What. The. Heck?! This was the only part of the book I really didn't like. It was contrived and.....weird.
I think that's all I'll say for now. Still pondering a few other things.