While I really like using MS Office 2013, I just can't use MS Office for Mac. It doesn't seem to integrate with the OS very well. I hope that the next version is better - hopefully retina screen support
I agree, it's painfully slow for anything but simple tasks. My former company (in)famously does everything in Excel (including Gant and flow charts), and being the only guy with OSX the load times were terrible, the UI sluggish and it crashed often. I was really quite surprised how snappy the UI was when looking at a coworker's windows box.