I do find it kind of ironic that a lot of people seem to agree that NF started going downhill when they split up the characters, but Kirsten Beyer did the the same thing in Voyager and everybody loves them. I'm even guilty of this myself. I guess she just must have managed to make it work where Peter David couldn't.
As for SCE and Vanguard, I've really enjoyed them both.
Vanguard is has a fascinating group of diverse characters in an interesting new area of space, with a great overarching story.
The SCE books are a lot of fun. They're most smaller more episodic stories, but the characters are really good. I do agree with Nasat that it does feel the most like another TV series of any of the book series.