UKH

Im thinking of buying either a Panasonic GX80 or an Olympus OM-D-10- mark ii. At various times they're about the same price and seem similar spec. 

Years ago, i use to shoot everything on manual 35mm Canons/Nikons in B&W and the manual control still appeals to me - for tgat reason, the Olympus is very appealing.

I have read that the Panasonic might have the edge optically though, so I am considering getting the Olympus body and a Panasonic 14-42 lens. Requirement is general travel - landscapes and street stuff where a light responsive camera is more useful than a proper SLR.

Any thoughts? 

Our household has both Pany and Oly bodies, same goes for Pany, Oly and third party lenses.

No problems what so ever.

Oh, and both manufacturers offer also manual focus on their AF lenses.

So go for what ever body feels better, and then get the suitable lenses for it... AFAIK the Oly is slightly bulkier (a'la dSLSR) in comparison to GX80 (more like Rangefinder). In fact, for streetphotos, E-PL or PEN might be the way to go for Oly.

For streetphotos, GX8/9 would be my pick... but more dough than the GX80.
https://www.dpreview.com/opinion/3394692865/gear-of-the-year-2018-carey-s-c...

In fact, as I focus more on to video these days, I'd look for secondhand GX8 .

For the record, what we have is the following:
- Old Pany GF3 (gave it to our 3 year old, with old 15mm/f8 lenscap lens).

- Pany GX800 (my small climbing camera, also 2nd angle 4K video).

- Oly E-PL5 (or 6, can't remember... might take the best pics of the bunch, atleast straight from the camera. Wife uses this mainly, and I use it to shoot others climbing).

- Pany GH4R (my 4k video camera, also my "big" camera when shooting pics... prefer this, when using manual focus lenses... takes more work in post, but might produce better stills than the Oly... but with more work).

Ive got a Olympus EM-5 on which I use a Panasonic 15mm lens which is very good, I’ve heard good things about Panasonic other MFT lenses so get the lens that best suit your requirements regardless of who makes it.

The Panasonic 12-32mm is probably the best of the kit lenses.

E-M10 II:

Better looking (IMHO)

Better sensor for long exposures i.e. astro (less noise)

Good features for long exposures (live composite)

GX80:

Better for video (4k)

Better for fast moving subjects (better continuous autofocus due to Panasonic DfD tech)

--------------

Panasonic and Olympus lenses work fine on each others bodies, however its not seamless.

Dual IS only works with Oly lenses on Oly body and Pana lens on Pana body.

Panasonic lens aperture rings dont work on Oly bodies

Some Pana lenses exhibit purple fringing on Oly bodies due to the weaker UV filter in Oly bodies. Not big issue but noticeable in some specific situations (http://alanwatsonforster.org/writing/mft-purple.html)

The Lens-FN button on Oly PRO lenses doesn't work on Pana bodies

I'm a bit biased towards the Olympus bodies. I think they are great. I've been using them for the last 2 years and have used Oly and Pana lenses with them and I think they are all pretty good. 

I've had the EM-10 mark ii since Jan 2017 and I've just put it up on ebay along with the 12-42mm and 40-150mm kit lenses. If you want to have a look at the listing drop me a message.

I've now got the EM-5 mark ii along with the PRO lenses and think the system is great for bringing hiking and climbing etc.

Can't comment on Olympus.  I have a now historic Panny.  The 14-45mm lense is very good for image quality. The compact power zoom 14-42 is less so, yes it results in a much more portable setup but at significant compromise. Just in case you were thinking of the PZ.