I bought the GX80+15/1.7 combination this summer primarily to dip my toe into 4k video.
I already had an Olympus E-M5 mkI and 25/1.4.
It was really fun to use - super fast autofocus and great video - the IBIS and electronic stabilization are amazing as if the camera on a steady-cam.
The manual focus peaking and exposure zebra make the far more useable compared to the Olympus.
The lens is sharp and flare seems well controlled.
I've been spoilt a little through using a Leica M9; the CCD color is superior and the signal to noise and bit depth from the M9 results in more glossy images.
The GX80 images are a bit flatter and show more shadow noise - but it's not bad and rather like film grain at 100% crop.
I think it's a close thing image wise between the Ricoh GR and the GX80+15/1.7.
For speed the GX80+15/1.7 combo is the clear winner.
The down sides :
The viewfinder is sharp but a bit small, especially compared to a Leica RF.
The rear buttons are too easily pressed e.g. by the strap; similarly I turned the touch screen off.
The lower SNR and bit depth of micro43
Here are a few images from an overnight walk up Glen Tilt with just the 15/1.7 carried.
Looking down Glen Tilt after the rain cleared
Successful shooting party
Brewing my tea
Pools at the Chest of Dee
Pools of Dee at the top of the Lairig Ghru
My Bivvy campsite looking over Aviemore ( the wind dropped and 1,000,000 midges appeared 5 minutes after taking this photo trapping me in the bivvy bag )
Finally something a bit different :
4k video sample with the 25/1.4 @ 1.4 ( with x2 digital crop in camera ) camera held above my head - the tilt screen is very handy for this https://youtu.be/G6h689zC8AM