Being the huge Argento fanboy that I am, I ordered this Arrow Blu-ray along with my own country's version released by Blue Underground. After watching both twice, I personally prefer the Arrow, which surprised me because after much research on-line it seems most people prefer the Blue Underground. Even stranger, I've compared screencaps of both releases from review sites and actually preferred the Blue Underground version in the still images, but for some reason this Arrow release looks better in motion. I think the color palette plays an important part in conveying the atmosphere in this film, so it's very important to get it right. I found the Blue Underground's colors dark and bold (more 'horror movie' style) while the Arrow's were bright and almost neon (more 'dream-like'). Comparing the two, I find the Arrow's color palette suits the film better for me. The Blue Underground release seemed almost too dark in some places and the colors, while bold and beautiful, just weren't as bright and surreal as the Arrow's. I guess it's a simple question of if you like the dark, bold colors or the bright ones, but I know which one I preferred. I've also heard a lot of negative comments about Arrow's use of DNR, however there are a lot of scenes in this Arrow release that contain a good amount of grain in them so these accusations may be unfounded. I don't think they got carried away with the DNR--most shots just look cleaner, and as for the accusations the characters look "waxy", the flesh tones look fine to me.
I'll also add that the sound on this release is noticeably better than the Blue Underground, and I don't even have a sound system hooked up, just my regular TV speakers and I could still tell the difference.