If you use fuse, you will have issues. Apple doesn't allow any unsigned kernel modules in Yosemite, and a developer certificate can't sign kernel modules. (You

If you use fuse, you will have issues. Apple doesn't allow any unsigned kernel modules in Yosemite, and a developer certificate can't sign kernel modules. (You need need to apply to Apple for special permission.) There is a boot argument to turn this permissions checking off completely. There were some issues in the beta with large amounts of stuff in /usr/local (I think Apple is building a new /usr tree and copying stuff over very slowly.) I don't know if it was resolved in GM3, but with Mavericks -> GM2, the last "about a minute remaining" took five hours. For my laptop, I'm going to move /usr/local aside before I do the Mavericks -> Yosemite upgrade and move it back afterwards. (The installer doesn't seem to mess with /opt.) It took out my java 1.6. Java 1.7 was intact, but I was surprised to find that the info.plist in (my copy of) IntelliJ says it requires Java 1.6. I had to re-link some perl directories to get git-svn working again, I forget the details. If you're dual booting, Mavericks will rewrite the spotlight index on your Yosemite volume, if it sees it. I don't use zsh, iTerm works fine for me.