I have an E-P1 and I've really liked it. AF on the E-P1 is not slow, nor is it fast. It is different though and I would not recommend thinking that you are purchasing a dSLR when you hand over the money if you ever decide to buy one!
Without the viewfinder, it's a different type of camera, similar to a point and shoot but with much nicer images and that ability to switch lenses!!!
I have not found it difficult to use the LCD to compose a shot or check for focusing issues outside (and I've used it plenty in SUPER bright conditions... although some people will complain about glare and such, depends on how tolerant you are with this kind of thing as all LCDs will suffer from this... I just use the screen to compose, focus and to get information from the menus... a lot of people seem to use it like their 22" desktop monitor).
As for no flash... well, I do have a FL 36, but rarely have I put one on it as in most cases, the automatic WB and higher ISO have handled low light conditions quite well (some noise but hard to tell unless you blow pics up, however, most shots I've taken have been meant for web and not print... I use it mainly as a walkaround/street/fun camera...)
I love its size, it's looks, and its portability. A little pricey $$$ but I have no regrets on picking one up. It's small size and charming looks makes it SUPER easy to ask strangers if its ok to walk up to them and take pictures of them or their stuff... MUCH harder I find with my dSLR with big lenses...
Some pics taken with it recently outside during a very bright day...
Flickr: laulaus' Photostream