The best way to look at this is to bring in specific vendors and have a bake-off, or bring in an external consultant to do the study of the various products in the market. Also, understand that these measurements may not fit your environment.
Many of the challenges that are experienced in the environment may not have anything to do with the storage devices themselves.
Most outages are actually caused by a human error rather than an outage of the device itself. Just some food for thought.