Here is some Background:
Modern Ibis uses 5 Axes stabilisation, but the CIPA Test is still from 2012 and not updated to this.
So the claimed values of the manufactures could not be reached in real World.
So the values are not really interchangeable between brand or even models if the Ibis mechanism was a new one.
Long Time MFT was king of the Hill but with the last iterations, FF and even Medium Format caught up.
I think the difference today comes with the extremes:
How many secs can you take with wide angel lens
How long can you go with 300mm or even more.
So lets take a look a the points I mention:
Nikon fc is the first one having Image Stabilization linked to AF point
I could not believe this brings up much but have not seen test results. Also I doubt it is a help for very long exposure or long tele shots.
I think every brand has combined OIS / IBIS in their latest models. This should help on tele shots because OIS can handle them better.
Nikon fc is also the first Nikon having Pixel shift, Sony, Panasonic, Olympus and Fuji where early on this.
The Ibis moves the Sensor a bit between multiple shots so you can get a higher resolution image or an image with more accurate colours.
This needs a Tripod.
Panasonic and Olympus got Hand held Pixel shift witch is not so accurate as the "normal" Pixel shift but do not need a Tripod to work.
Pentax has a Star Tracking Mode witch can be used prevent star tails via Ibis.
The Olympus Om-1 as many handys has a On Screen help for long time exposure this should help to pin the camera on the same object on multi second shots. This might help to bring the max secs for wideangel shots even further.
Ibis might help on the following two Items:
Olympus has a Software ND Filter to combine multiple shots into one with lower EV.
Most Brand today have some kind of Focus Stacking combining multiple shots to one with a bigger Area in focus. This is mostly used for macro shots.