Tried the E-M5 yesterday..
Local place had one on demo. I was already fairly sure I was going to buy one to replace my GF1, but it needed to be tried first.
The viewfinder is quite nice! Better than I thought it was going to be! I didn't get the claustrophobic looking-through-dark-tunnel I get when looking through my old 350D optical VF. There's a bit of a screen-VF lag if you move your eye to and from it too quickly, and the VF can be activated sometimes if you move your hand too close to it.
Touch screen is okay. Didn't spend much time with it. The touch-focus seemed much more responsive than that of my friend's GF2.
AF is fast! The 12-50 that was on demo is too large, I will be using my primes with it. AF on my 45mm was speedy! Even the 20mm pancake felt more responsive than on the GF1, which I also had on me.
It was lighter and smaller than I expected. The "hump" doesn't bother me at all, but then again I come from a film SLR background.
Unfortunatelly I missed out on the first batch of body-only reservations. I'll have to wait 'till the second batch in 2-3 weeks or so.