I have had the E-PL1 for almost a year now. About a month ago, I purchased the Panasonic G2 (after toying with the idea of getting a GH2).
Here are my thoughts after using both for the past month:
Panasonic G2: In every way, except for the photos that result, this is the better camera. The EVF is a dream to use (and I use the VF-2 on the E-PL1), and the swivel screen comes in handy more often than not. I love how the EVF has a sensor so it automatically switches to the EVF when you bring your eye to it and automatically goes back to the LCD when you remove your eye from there. The LCD has a few different modes, but I leave it on the options mode (which is very similar to our Super Control Menu on the Olympus cameras). This allows you to use the G2 much like you would use any DSLR. You view through the EVF when composing, and the LCD screen has all of your options. The touch screen works really well. It allows you to just press on the option you want to change and I like it a lot more than fooling around with buttons.
I find the camera easier to grip, and the location of the buttons and dials makes sense. I like how in a lot of cases, they have choosen to use sliders or dials instead of buttons. It allows you to skip the menus altogether and just flip the switch that you need (for AF-type, shooting-modes, etc). The menu is very detailed, but not overwhelming at all.
AF is faster than the E-PL1 and there is no contest between the two. AF on the G2 with the 7-14mm or 14-140mm especially, is so quick that you don't notice any hunting at all. You press the shutter, and you get the focus confirm right away. I dare say it's as quick as a DSLR (and I used to use the E-3 w/12-60mm SWD and 50-200mm SWD).
Olympus E-PL1: The main benefits the Olympus E-PL1 has over the Panasonic G2 are In-Body Image Stabilization and it's beautiful out of camera JPEGS. Here is where the actual pictures come out amazingly well without any need to tinker with it in a RAW editor. The IBIS is great because you get IS on ANY lens you use, whether it is a 4/3 lens, u4/3 lens, legacy glass, whatever! Don't underestimate the power of this. Also, a small benefit is that the E-PL1 is a smaller body than the G2, but as soon as you put on the VF-2, it becomes more cumbersome to use than the G2.
A small benefit that the E-PL1 has, but only because of it's inferior LCD screen, is that when manually focusing you'll notice a glitter (actually aliasing) at the focus plane. This greatly helps when using manual focus with legacy glass in that you don't even have to zoom in when focusing, you just watch when your subject gets a little glitter over it and you'll be in focus. This doesn't happen on the Panasonic G2, because of the higher resolution LCD (as I'm told).
Overall:
If Olympus would build a u4/3 body with a built in EVF, and a swivel screen I don't think I'd have any reason to even consider the Panasonic range of bodies. If Panasonic would put IBIS into their bodies, I don't think I would need another Olympus body.
Unfortunately they both have their trade-offs, it just depends which is more important to you. Since getting the G2, I haven't used the E-PL1 at all. I've slapped the 20/1.7 on it and thrown it in my kit bag. But whenever I reach for a camera it's been the G2 with the 7-14mm or 14-140mm. I'll likely only use the E-PL1 for those situations where I know I'll need IBIS, or a P&S looking camera (for certain venues which don't allow DSLR cameras).
On a related note: I bought my Panasonic G2 (body only) used for $350. That is a screaming deal you are getting here. Kind of makes me think that there is a G3 JUST around the corner...
