If you are interested in the EOS R, maybe you might want to hold off until the next-gen model because according to a report from Canon Rumors, it seems that Canon’s next EOS R could come with a 5-axis IBIS (in-body image stabilization). Now there are IBIS and lens-based image stabilization, where the former will allow for stability across all lenses, whereas the other is localized to the lens that is attached to the camera.
The former does seem to be better as it will be applicable to any lens attached to the camera, although in the past Canon has claimed that they do prefer lens-based stabilization over a sensor-based stabilization, but if this rumor is true, Canon could be having a change of heart. Of course whether or not this is true remains to be seen, but if you do prefer IBIS over lens-based stabilization, then the next EOS R model might be worth waiting for.
In the meantime we have been hearing rumors that Canon might have a new high-res EOS R launching at Photokina 2019 and that there will be at least two new models planned for 2019, so we’ll just have to wait until then for the details, so until then take it with a grain of salt.