I have just bought an Olympus Pen. I had been thinking of getting a micro 4/3 camera for some time, as a nice compromise between my 40D and a point and shoot. Ever since I saw one being used to good effect whilst doing my winter skills training in 2010. I spent a lot of time comparing the Olympus and Panasonic systems. Eventually Tesco made me an offer on the E-PL1 that I couldn't refuse (never underestimate the power of the clubcard point).
Thanks to the very 'mixed' bank holiday weather, I haven't had much chance to play with it yet. I did manage a few shots around Cambridge on Sunday afternoon. I am still learning the controls. I can work the buttons on my 40D instinctively, without looking at them (handy in the dark or during action shots when you don't have the time to take the camera from your eye). This caused a few issues, as I 'instinctively' pushed the wrong buttons on the Pen, but that's just me and not the camera. Having to rely on the LCD for framing shots is also new to me (even my point and shoot has a viewfinder). Still, initial thoughts are positive. I like the flexibility that the small size of the Pen gives me.