The E-PL7 image quality and high ISO performance is identical to the E-PL5 with more subtle/natural colors, less saturated colors than the E-PL5. The image quality and high ISO performance is excellent up to ISO 6400. I did notice some slight advantage in terms of noise compared to the E-M5 and E-P5, but those were only noticeable when looking at 100% scale image. The difference might be due to the different processor. You can check out imaging resource comparometer tool to observe the differences yourself. Overall, I wouldn’t pick any one camera over the other in terms of image quality and high ISO performance, as all four offer around the same performance.
This means that you will give more weight to the camera features. Olympus did add more creative options to the E-PL7, but that’s something that we might see in future firmware update on the other models. I think that the Olympus PEN E-PL7 main selling point is its selfie-friendly tilting display, great design, small size, excellent AF system and the Wi-Fi wireless features, all that backed up with excellent image quality and impressive high ISO performance.
The E-P5 costs around $200 more, and I find it hard to justify the extra price. The E-P5 advantages over the E-PL7 are the 5-axis IBIS, 1/8000 sec shutter speed (mechanical shutter), better build-quality, built-in flash, faster flash x sync speed, slightly faster burst (but with subject tracking) and more flexible exposure compensation. I think that all in all, the E-PL7 offers an excellent value compared to the E-P5 for those who don’t find those advantages that useful for their type of shooting style.
The OM-D E-M10 comes with a built-in EVF, built-in flash, improved ergonomics, more buttons and dials that offer fast access to frequently used functions, and for extra $100, I think that some of you might, although its larger size, that the E-M10 worth the investment for its built-in EVF, advanced button layout and design. The E-M5 is a step above the E-M10 and brings some great features like the weather-sealing, 5-axis IBIS, built-in EVF, 9 fps burst but it lacks the built-in WiFi feature.
The E-M5 will appeal to outdoor photogoraphers and those who might prefer the larger body when using large and heavy lenses, as it helps to better stabilize the weight, especially if you also intend to use an external flash as well.