2. R2 doesn't support file versioning like S3. As I understand it, Wasabi supports it.
3. R2's storage pricing is designed for frequently accessed files. They charge a flat $0.015 per GB-month stored. This is a lot cheaper than S3 Standard standard pricing ($0.023 per GB-month), but more expensive than Glacier and marginally more expensive than S3 Standard - Infrequent Access. Wasabi is even cheaper at $0.0068 per GB-month but with a 1 TB billing minimum.
4. If you want public access to the files in your S3 bucket using your own domain name, you can create a CNAME record with whatever DNS provider you use. With R2 you cannot use a custom domain unless the domain is set up in Cloudflare. I had to register a new domain name for this purpose since I could not switch DNS providers for something like this.
5. If you care about the geographical region your data is stored in, AWS has way more options. At a previous job I needed to control the specific US state my data was in, which is easy to do in AWS if there is an AWS Region there. In contrast R2 and Wasabi both have few options. R2 has a "Jurisdictional Restriction" feature in Beta right now to restrict data to a specific legal jurisdiction, but they only support EU right now. Not helpful if you need your data to be stored in Brazil or something.