Drop Dead Gorgeous is the best! I've also read Quality of Mercy & The Way We Get By, so far. Definitely good stuff. I found Transfigurations solid, once I got past the running off to Florida and the new Hermione...

Secrets is hugely long, and probably my next favorite after DDG for the mo'. I almost didn't read it because of some of the setup in the first chapter (i.e., Victoria). I'm glad I stuck it out, though, because the characterization really worked for me, as did the plot. I ended up rereading Half-Blood Prince again just to see if Secrets worked as well as a sequel as I thought. It did!