Over in the Open Gear forum thread https://www.photographerslounge.org/f16/serious-compact-great-low-light-has-good-resolution-120/index2.html#post403, Dunkeld asked a question that I think deserves a new thread, so I've copied the first response here, in hopes of kicking off more conversation.
The E-PL1 has a slower shutter speed maximum, too. It goes up to 1/2000 while the E-P2 ranges to 1/4000 - thus far this has not been a problem for me.Dunkeld wrote "So how does the EP-L1 compare to the E-P2? Does the EP-2 warrant the extra cost?"
The optics and sensor are the same. But the E-PL1 has a popup flash that is missing on the E-P2. If you buy the accessory flash for the E-P2, you have to take off that great EVF to install it. The same EVF is available for the E-PL1 but can be used while doing flash photography. And a cool trick - you can easily pull back the little E-PL1 popup flash with a finger so it points upward, allowing easy bounce flash, and this works well!
E-PL1 negatives: lower resolution on the display (not a problem if you use the EVF), and no adjustment wheel. So you press buttons more. I've gotten used to the interface so I'm not bothered, but I think that's the main advantage of the E-P2.