The edition of the trilogy I read has an interesting afterword by Kim Stanley Robinson, which said among other things that the friends of PKD/Horselover Fat's in
VALIS named Kevin and David are supposed to represent KW Jeter and Tim Powers, which I find amusing and interesting as a big Powers fan. He also argued that Angel Archer was the voice of a reintegrated real PKD, no longer the sundered parts of "Phil Dick" and"Horselover Fat" from
VALIS. Maybe that's why I liked
Transmigration the best, it was the most interesting authorial voice of the three for me. The Dick/Fat split made for a lot of cognitive dissonance for the reader, which was of course part of the point I think, but it wasn't always that pleasant. Angel stoned and reading
Howard the Duck while her husband ranted about Wallenstein and Hitler was classic.
Past Master looks promising, it's about a troubled future society bringing Sir Thomas More ahead in time to help run their world.
I've never read
Frankenstein either, it's on the short list going forward.