Oly OM-D E-M5: What's quirky about it?

From my experience renting one for a week for a project:

The AF point behavior is quirky: the points are bigger than you'd often like, and the only way to get them smaller is to use Preview Magnify before autofocusing.

The "dial-a-tone-curve" feature is quirky, but sometimes useful (and you can certainly ignore it, in the vein of Olympus loading their cameras up with optional features that you can use if you like them and ignore if you don't).

The layout of the control dials is a little quirky and nontraditional, but they work just fine.

Continuous tracking AF is quirky, in that it sometimes works and sometimes doesn't and sometimes decides that a chair in the background is VERY interesting.

Overall it's a very easy camera to take good pictures with; in my opinion, like the Four Thirds series has from the beginning, it just does a lot of things right. I have experience with Olympus DSLR's, and it was easy as pie to slap a lens on it and shoot. Coming from the Panasonic sensor era, the color rendition is definitely different, but that's no bad thing; it reminds me more than anything else of looking at Kodachrome slides.