Oh, honestly I don't know... I have as of yet only read her Avalon series (some of them since I thought they were long winded and a bit boring) and the Trillium series
. Thought those last were fantastic, only that's been about 15 years since I read em (kid back then) so don't remember them all too clearly.
Oh and I see now that the Trillium series is not all from Marion Zimmer Bradley, but in cooperation with Julian May and Andre Norton.