That's what a lot of people say, OM camera can get to a second of 2.
I can my gx85 and 12-32 to only 1 forth of a second of stable image(about the same with my x-t2 and 16-50), i wonder if i switch to e-m10 ii would make a different. I understand OM camera doesn't do duel IS with panasonic lens.
The E-M10 II is a nice camera (I had two myself), but its stabilisation is not as good as the newer and better ones like the E-M1 II or III and the OM-1. Also the E-M10 II doesn't do dual IS (or Sync IS as it is called by Olympus) with any lens at all. Lastly, how many seconds you can do handheld depends first and foremost by how stable your own hands are and your holding technique, and only in the second place by how good your camera's IS is.
IMHO it is a matter of how good your handholding skill would be.
The IBIS alone of Panasonic, saved for G9 etc flagship models, are far from the best.
On GX85, partially due to its body shape (soap like RF form factor, small and no real front grip) just making it less effective. As per my humble experience, IBIS of GX85 is no better than 2+ ~ <3 stops. I guess the IS prority of Panny should have reflected this: DUAL IS 2 > DUAL IS > Lens IS > IBIS. :-)
However the overall IS of Panny bets on DUAL IS. As per Richard Wong who is an active Panny gear reviewer (on DOR and Utube), had tested the rather primitive DUAL IS of GX8 should already match that, if not better, than the IBIS of EM5 mk-II. So a DUAL IS compatible lens is critical for GX85, even so for G85.
Pairing with 14~140 I could get 5 stops solid effective IS on GX85. Not the best, but should be reasonably good enough for a low cost model?
TBH I can't handhold my DUAL IS setup for slower than 1/4" (sharp at 1:1). But some reports on DOR suggested they might do it on sec zone for similar setup. Just I am lacking of the skill and stability only. :-(
As another poster mentioned, it depends on the camera and also the connected lenses. I have an Oly E-M5 Mk iii and a Pan G9. I wouldn’t say either has a clear advantage over the other overall. If you add a lens with no IS, the IBIS in each works quite effectively up to about 150mm. The Oly handles larger shake compensation slightly more predictably than the Pan. If you add a lens with IS, for best stabilization you will need to pair body to lens from the same manufacturer.
Therefore to answer the question, I would first consider which IS -based lenses supporting Dual IS or Sync IS you have or will buy. Then choose the camera based on which you will use most. Pan has many more IS lenses but the few that Oly has are very good but pricey.
It is more than numbers measured in a laboratory or what you can learn from others experience.
If you are leaning against a brick wall, use proper camera holding techniques, have steady hands, and squeeze the shutter smoothly you'll have better results than if you don't.
Focal length is extremely important. You said 1/4 seconds with the 12-32. At 12mm you can probably get a shutter speed more than twice what you can at 32mm.
Electronic shutter is preferable as there is no shutter movement to slightly jar the camera.
And, of course, some cameras have better stabilization than others, and that does not coincide 100% between manufacturers. Some Panasonics are better than some OMDS/Olympus and vice versa. Currently, the OM-1 is probably the best, followed by the most recent OMDS/Olympus models. IDK the GH6 but the G9 is pretty good too and only very slightly below the O. "cream of the crop".
Above all, take at least three photos, if circumstance permits. Even for the steady handed, shakiness is rather random and can ruin shots at any shutter speed.