It's just brutal in Yosemite. This is the first release to which I regret upgrading. I've never had so many issues on my laptop, and it has never been so slow. My FileVault encryption has been stuck at 99% since I upgraded and enabled, and Apple marked my radar report as a duplicate. They can't/won't tell me if I'm forever hooped or if it will ever be fixed. At this point, I'm looking to spend a day rebuilding my whole system.