I don't know about R2 specifically, but we migrated one of our service from S3 to Cloudflare Images, and we have been hit with over 40h+ of down time on CF's side over the last 30 days. One of the outage was 22 hours long. Today's outage has been ongoing for almost 12 hours and is still ongoing, and we have had 2 or 3 others >1h outages.
Every cloud provider has outages sometimes but CF has been horrendous.
We were actually planning on migrating some other parts to R2 but we are just ditching CF altogether and just going to pay a bit more on AWS for reliability.
So if R2 has been impacted even a third as much as CF images, that would definitely be an important consideration.