Thank you for the elaborated post Rob.
I agree with you when you say, "Storage performance in the end always comes down to the physical storage medium"
Considering that in mind, If you could explain the importance of RTO and RPO while as a customer/Implementation Specialist, What do you keep in mind at planning stage?
Peformance comes with the cost! However, having said that it also on Storage Admins to make the right choice depending on the storage system.
I always recommend following configuration depending on the customer's requirement:
Performance: RAID 1 + 0 (Expensive compared to RAID 5 but gives better performance)
Capcaity + Performance: RAID 5.
Moreover, if you could share your experience for EMC CLARiiON Storage Systems for Best Performance Practices in Industry for different types of Servers/Applications. (MS Exchange, Database Server etc.)