Mir, it never delivered the performance that was promised, and I've never liked unity it's a hassle to use. I just wanted my applications, I don't want to be online 24/7 searching from my app launcher for things I know are on my hard drive. I don't care for eye candy, it's cool to look at the first week or two, but I quickly find myself disabling every transition effect I can find to get those few ms of performance I want from my OS.