I'm curious what's up with the colors myself! Every previous DVD release has had harsh contrast and boosted saturation, similar to how I'd expect a vintage Technicolor feature to look - but as others have said, this was shot on Eastman film, so there shouldn't be a reason for the film's colors to "glow" like they do on all the older transfers. Was this because Anchor Bay (et al.) were emulating the look of Bava's older features like Blood and Black Lace, or were the prints they were given processed to look that way?
All the stills of the Blu-ray look just a bit anemic to me, but the improvements in detail and contrast seem well worth the color being a bit dull. Not to mention we get the "Psuedotechnicolor" Italian version in full as an extra.
Odds are the negative has always looked this way, or maybe it's faded a bit in the last 40 years and that's as good as it'll look now. It looks very promising (especially if I adjust my monitor for the evening!), it's just not how I'm used to the film looking.