I bought it when it was released and installed it on a Macbook. I wasn't able to install it without formatting the hard drive. I ran it for a few weeks, found it pretty stable, and then installed it on two iMacs (no installation issues; didn't have to do clean installs). Was it worth it? It does have some new features that I like, but there's nothing ground-breaking. I haven't noticed any difference as far as audio is concerned, and no, flac is still not supported by of CoreAudio or iTunes