I was lucky enough try out the Olympus E-M1X yesterday at a rugby session. I already have an E-M1 Mark II so I am familiar with the MFT range from Olympus.
The reason I bought an E-M1 is I have a few Canon DSLR's and wanted something lighter. The Mark II gives me that and to a lesser extent so does the E-M1X.
The E-M1X does really feel well balanced. I was using the 12-100 F4 and it really did work together well in both landscape and portrait orientations for shooting. I do not have big hands and feels more comfortable than my 1D. Saying that I have the battery grip for the Mark II and it is still in the box. I see no need for it. Swapping a battery out is a couple of seconds work and as I said above, I want a smaller camera.
I do like the functions and controls on the E-M1X. They are just a little better placed than the Mark II (this could purely be down to the extra size). I really like the separate Bracket and ISO buttons (I use these functions frequently). The joy stick is a nice feature too, The back wheel is also flush and not situated on top as it is on the Mark II - I feels more natural to use.
The menu structure is the same but of course has far more features as you would expect. Easy enough to use.
IQ -the light was not bad in the morning so was using ISO in the 640 to 1000 range. I would say it is probably 1-stop better IQ (ie. results on E-M1X at 800 is same as 640 on Mark II). I did not use the Olympus at the match in the afternoon my 7D2 was up around the 3200 mark and was still better than Olympus.
The FPS rate is far higher on the E-M1X. I did not put it on High burst rate (18 FPS) but kept it on Low (10 FPS) as that is more than adequate for what I was taking photographs off.
The features I know are there but did not test out - Hi Res hand held shot seems good. IS, not for sport. Improved AF - I only use spot focus. Movies - not for me.
So do I like the E-M1X over the Mark II? Even though it is bigger, yes I do.
Would I buy it? The E-M1X retails at £2800 and the Mark II at £1400. It needs to be twice as good and for what I want, it is not that value. Better camera for sure and I would take it over the Mark II at the same value. But it is not.
