Surprisingly I find Digital IS pretty capable on the EOS R so far, with only a small extra crop but a LOT more steady compared to nothing... And competitive with IBIS... which is the most surprising thing. There aren't any artefacts from micro-jitter. It's pretty well locked down. Even pans work out well.
IBIS on the Z7 is superior, but yes the floaty look is there and not very cinematic. The lazy temptation is there to use it and leave your handheld camera skills and tripod at home
The Z7 IBIS seems in-between Sony and Panasonic for effectiveness, so it's an improvement on the A7 III but not as good as a GH5.
I'd put the EOS R DIS in between the two as well. So actually more locked down than an A7 III.
So far the EOS R is earning a bit of a niche for itself in my crowded camera bag. And that too is unexpected.
It's a bit like a Canon GH5S.
That also has a 1.8x crop and no IBIS.
On the EOS R we have 480Mbit ALL-I or 120Mbit IPB codec so pretty similar to the GH5S as well. The 10bit vs 8bit issue is controversial and needs proper testing, because the Canon colours appear at first impressions to bridge the gap or even exceed how pleasing the 10bit files are on the GH5S.
Even the ergonomics feel similar between the two cameras. Both have very similar screen quality, same articulated design, similar EVF resolution and size.
The one area the GH5S is definitely superior is rolling shutter.
But the EOS R is FAR superior for video AF and tracking.
Also it is a 5D Mark IV standard full frame camera with your EF lenses for stills and 1080p, whereas the GH5S requires a Speed Booster to get close to that look and it is not 30MP.
Stay tuned for my EOS R review tomorrow, it may surprise.