IQ is best on the EPL1, and all others after the EPL1 (EPL2, EPM1, EP3, EPL3) have lesser IQ and higher ISO capability instead, is this correct?
No, I don't think so. My understanding, derived from a great deal of reading at the various MFT sites, plus ownership of three different Olympus PEN models, is that the weak AA filter was carried forward into all future models as well. At least, this is the consensus of those intimately familiar with MFT.
I've performed my own IQ
comparison test between the E-P2 and the E-PL2. The latter clearly shows the effects of the weaker AA. The difference between the original stronger AA models and the later weaker AA models is small but significant. The difference between models which have a weak AA would be minuscule indeed.
What about the AF? is the EPL1 AF slower than the others, or is AF dependent on the version of kit lens? I read that the MSC 14-42 ii lens had faster AF than the original 14-42, can anyone confirm/deny this?
AF depends on the specific lens and the camera body, but the most important factor is the lens. For example, the Panasonic 20mm is slow compared to the silent and blindingly fast Panasonic 14mm. Yes, the revised kit zoom is supposed to be faster (and quieter) than the original. Though I own both, I can't be bothered to use a zoom and so I can't confirm this first-hand.
I have written up an
Overview of the Olympus PEN range, since it is surely confusing! If you want the fastest AF, most responsive camera, best burst rate, etc. then you should target the E-PM1 or E-PL3. (The E-P3 has most
but not all of the same advantages. It has always seemed over-priced to me.)
a EPM1 would be even better - all the ability of the EP3 but about the size of an LX5...but if IQ peaked with the EPL1, thats the version to get since I am not looking for the absolute smallest rig here...
The E-PL1 has several disadvantages compared to other PEN models. It is limited to 1/2000 shutter, cannot use a wired shutter release, and has a rather poor plastic build. Instead consider the E-PL2, which can also be obtained inexpensively. It has none of those drawbacks, plus gives you twice the LCD resolution and a sizeable grip (that's a big deal to me).
The E-PM1 is another animal entirely; the ergonomics are much more like a point'n'shoot. Many would consider the size, lack of controls, lack of grip, and overall form factor as negative factors.