The E-PL5 has a tilting screen. The E-PM3 does not.

The E-M5 sets a new benchmark for Micro Four Thirds images, thanks to a modern sensor and Olympus' excellent JPEG engine. It continues to produce good results in lower light than was previously practical and produces attractive output in all but the most challenging of situations. The combination of its small body and the small lenses available for it (specifically the Panasonic 20mm F1.7 and Olympus 45mm F1.8) mean it's a camera we found ourselves taking everywhere, without any concerns that we were having to make undue compromises on image quality.

The E-M5 can't completely overcome the light capture disadvantage brought by its smaller sensor, compared to APS-C, but it reduces it to the point that it's irrelevant for almost all practical purposes. At which point we think its size advantage, in terms of both body and lenses, will outweigh that difference for most uses. If you're absolutely unwilling to compromise on image quality then spending twice the money and moving up to the bulk of full-frame is the only way of gaining a significant step up from the E-M5.

This capability, combined with an increasingly useful range of comparatively affordable fast lenses (the largest of any mirrorless system), makes it easy to get good results from a variety of shooting situations, even when the light gets challenging. The camera's default noise reduction and sharpening settings aren't entirely to our taste but they're not overly destructive and are easily changed for the better. That minor gripe aside, we've been impressed with the E-M5's output, whether in Raw or JPEG.