Jono,
I've had the same reaction to the E-P1.
I had the G1. I thought it was a nice camera, and well conceived/designed for it's purpose. But I just never really
loved shooting it. I always felt like I was using a super-zoom digicam, and the visceral experience of shooting with it just wasn't great for me. I was happy enough with the images, and would use the G1 when traveling, but only when my larger Canon system was too inconvenient.
Along comes the E-P1, and it's completely different for me. The shooting experience is far more like the M8 (which seems odd, given the lack of a VF) than it is like a G1. The feel and handling of the camera is completely different, and just fits me much better. I actually look forward to shooting the E-P1, and will grab it in situations that I could just as easily take the Canon system, just because the E-P1 is so enjoyable to shoot.
With my Leica M lenses (50 lux and 75 summarit), I can walk around for hours, having fun just shooting stuff with the E-P1, the way I used to with my M8.
The E-P1 certainly still has it's limitations and flaws, which need to be addressed in future generations. The AF is far too slow to use for sports/action shooting, and doesn't work at all in very low light. And at some point, some type of VF will be necessary (rangefinder style, EVF, etc).
Even with its flaws and limitations, I'm really enjoying the E-P1, and it's put the fun back in "walk-around" photography for me, which I haven't had for a while.
HI Simon
Not like that - I got rid of the G1 after a month, I just didn't like the way it worked. The E-P1 seems a huge improvement to me - mind you, I've always cordially disliked EVF viewfinders (paint me as odd)
The Olympus user interface is pretty good, and if the autofocus is slower than the G1 . . . it's close enough. Throw in a rather delightful ergonomics and autofocus with all the 4/3 lenses.
So, it might be 'what you're willing to put up with' with the DP1/2, but the E-P1 is (and I'm not alone in this feeling) a delightful camera, which the G1 wasn't quite (good - yes, delightful - no).