Slightly higher latency. I've seen about 20-30% increase from S3 to R2. But the bill is magnitudes lower.
Agree with the KV point, Upstash is the same. But I just use dragonflydb on a single VM. No point paying for transactions.
Hell, S3 could have 20ms latency and it wouldn't matter since I can't afford it.
Where are you seeing orders of magnitude lower R2 bills? The storage price for S3 is $0.023 per GB, and the price for CF is $0.015 per GB. The operation pricing is even more similar - S3 is $5/million writes and $0.40/million reads, while Cloudflare is $4.50/million writes and $0.36/million reads.
Egress fees are the largest part of many AWS bills, this is by design, that price is deceptive. R2 has no egress fees.