It seems that Allies is the point in the Fate of the Jedi series where things start picking up.
Luke, Ben, and the Sith make a temporary alliance to go and fight Abeloth, and attacks against the Jedi on Coruscant start getting pretty bad. (Though this book marks the end of the force psychosis plot).
Allies wasn't bad, though I don't think I'm much of a fan of the way Christie Golden writes. I thought it was weird how Ben and Vestara became randomly attracted to each other when in Backlash, they barely even interacted. Some things at the end weren't very clear, but I'm going to assume that it will all be explained later.
Something that I liked was the authors bringing back the character Callista after her last appearance in Planet Of Twilight. I think it's cool that we finally get to read about her fate in this series.