I have the GX7 and E-M1 and like both cameras - I consider them pretty much an equivalent even as they are. The technical size is similar but the GX7 following the RF style is more compact and packs away better. I have not particularly noticed my photography being hindered in any way by a lesser-type of IBIS. The E-M1 has a few nice points such as the way it has more direct control over the magnified screen. But its control layout whilst quite acceptable is all over the place compared to the GX7. The menu sytem on the GX7 is better conceived than that of the E-M1. And of course the GX7 is rock solid reliable by comparison. The E-M1 offers a huge grip by comparison, an optional battery pack, and dslr styling for those that need this. When I use smart adapters with Canon EF lenses I cannot see any real difference between the handling and imaging performance between the two. Any real size difference is not relevant.
I do like my E-M1 though and use it regularly. However I approach the comparison without Olympus blinkers on.
I assume that the E-M1 MkII will improve performance compared to the current model.
I am a bit lost as to what a MkII E-M1 could provide that might make it more attractive to me.
I want more PDAF sensor points and I want the camera to focus on horizontal targets as quickly as vertical ones when using PDAF. What I really want is a global shutter so there is no blackout with sequential images, but I doubt that will happen.
It is hard to see many areas where the E-M1ii might be improved within its current design concept - maybe a 20mp sensor and even more retro style can be thrown at it. But Olympus badly need to rethink their bitty control structure and menu system for better convenience. I illustrate by noting one item: things like waiting for the last capture to record before a playback can be requested seems a feature that is an Olympus trademark and a minor frustration.Other cameras allow and remember a playback request even if the user still has to wait until the last image has finished recording before playback appears. I use playback on demand only and I disable my auto playback at every capture on all my camera bodies so this might be why this has been unnoticed by others.
I turn off the image review and look at previous images only when I have a concern about lighting and correct exposure. However, that would typically be after only one image & check it, a second image and check it, so there is little waiting on a single image.
Whereas the GX7 flows naturally I have to think about which button I should press more often on the E-M1. I have customised controls on both bodies to my taste.
The GX80 is more likely to appeal to users who would consider the E-M10 MkII.
I suggest that the GX80 is right up there with the E-M1 and will blow the E-M10ii away in terms of performace.
I guess that depends on one's interest. There is little difference in image quality on any of the mFTs cameras. My E-M10 serves quite well for most photography, other than wildlife photography. The GX80 may have better CAF performance than the E-M10, but I would not use either for wildlife. For individuals who want better video, the GX80 is the obvious choice (not important to me, I have never used the video on my E-M1 or E-M10).