CPU-bound workloads are not particularly rare. Also, EBS is your only storage option for any data you might care about. 90% of the reason RDS exists is because I/O is so bad on normal EC2 instances.
You can run a database just fine using provisioned IOPS EBS especially in a RAID 10 configuration. I'd like to see some data to the contrary as I've actually done it.
There's some disadvantages to using RAID 0 with EBS volumes in a performance dependent situation.
Since you're writing to multiple EBS volumes for the RAID 1 portion of the RAID 10, you're going to require more EC2 to EBS bandwidth.
EBS volumes are replicated across multiple servers, so you don't necessarily need the reliability, especially if you're replicating the data elsewhere.
YMMV, of course, and everyone has different priorities and different levels of what constitutes acceptable risk, but RAID 0 with EBS isn't quite the data death wish it is with physical hardware.
> EBS is your only storage option for any data you might care about.
No, it's not. It is if you want data-at-rest storage, but I don't care about that when I have multi-master MySQL and Postgres running on instance stores. Or when I have replicative NoSQL databases (Riak is more than happy running forever in instance stores and duping across AZs).
