Vortex is the sixth book in the Fate of the Jedi series and I think I've realized I don't really care for this series. Yeah, the plotline with the Sith could be interesting, but all the characters are one-dimensional caricatures. The bad guys are uniformly selfish and the good guys have all the answers. Luke Skywalker has been upgraded to near Superman status and it's a bit annoying.
Denning might be a decent writer, but he doesn't have much to work with here. I think the best part of the Expanded Universe is learning about stuff that wasn't covered in the movies. This series is attempting to recapture the epicness of the movies where every decision has ramifications across the universe. It's ok to read some books in that style, but I wouldn't mind something a bit more everyday.
I only recommend this book if you're determined to plow through the series just to see what the heck happens.