Well, I know I'm in the minority but I've always found their stories intriguing. The 2 Phoenix novels, while heavy-handed with the alpha male concept, gave us a perfect villain in Omne. He knew how to manipulate Kirk and Spock and that made him very dangerous. Those novels were better than some of the others at the time like World Without End
or Spock, Messiah!
I didn't care for their take on Vulcans in The Prometheus Design
but it was still an interesting look into an alien, if not Vulcan, culture.
was rather simplistic (read: Mary Sue story) with a triangle with Sola Thane. But it was a nice insight on Kirk and Spock putting each other first above their own needs.
The Procrustean Petard
in Star Trek: The New Voyages 2
was too chauvinistic for my tastes but it had an interesting germ of an idea that was executed poorly (much like Turnabout Intruder
Lots of interesting ideas from these two ladies!! Not always the best Star Trek
but a bunch of stories I would include in my own personal canon with some polishing and streamlining on them.