If you’re thinking CoverFlow in the Finder in 10.5 is going to be useless, I’ve got one word for you, just one. “Previews”.
It’s been impossible to get big previews of files in list view. “Icon previews” in icon view, yes, but nothing in list view. Perhaps understandable - where the hell would you stick those icons? Since CoverFlow view has a list view below, it solves the problem, and you can see several, big previews simultaneously.
What’s more, there’s been reports that the Finder in 10.5 is just plain faster overall. The Finder, as long as it sticks to its current plan of being half-a-browser, half-spatial, will never be really great, but with better network browsing, faster Spotlight searches, faster overall file-shuffling performance and a well thought-out plan for easily previewing stuff (Quick Look, CoverFlow and what I assume are blazing-fast icon previews) it’s going to suck a lot less and be a better implementation of the same concept. Until OS XI shows up (and, unless Apple’s willing to go to 10.10 just as easily as 10.4.10, they’ve gotta be planning for it now), I’m happy with that.