I believe you're mixing a few things up. Enterprise disks are created for servers, which require a high reliability. It in no way, means they are also better on other fields. Hell, usually Enterprise disks are behind the regular disks when it comes to size.
Also, faster != better. For disks now-a-days you really need to take a good look at what you want to do with them. For example, I have a NAS I just fitted with new drives. I'm personally a fan of Western Digital, so I was looking at either the Purple or Red series. I'm using the NAS to store my video to it, so you could recon I should pick the Purple, because it's for video right ? Well not exactly. Since we use Milestone here, we have a live database and an archive. The NAS is the archive. Video is being stored there after x-hours. So if we look at behaviour, it's no different from a regular NAS storing regular data. So we went for the Red series. Red PRO in this case, due to the size of the NAS.
If you look at the difference between Purple and Red. Purple is basicly a Red but with different firmware where it's optimalised for data being constantly written towards it. Where as Red is different from the other drives (Black, Green, Blue etc.) in that it's good with handling higher tempertaturs and micro vibrations which you see in NAS systems.
So there's no real streight awnser, for selecting a drive you need to take a good look and where you will place it, and how you are going to use it. As for drive speeds, if I have the fastest drive in the world, and only use it to look at Video, then the maximum speed required to play that video is all the maximum speed I need for it. The rest is just waste.
Last tip, don't ever use Seagate.
I'm no tech, but if money is no object then I choose solid state drives.
IPVMU Certified | 01/09/15 02:50pm
Be sure to pay attention to the 'System Vibration Tolerance'....it is a real thing to be aware of.
It means that the drive is affected by the spinning of its neighbors...and will cause data failures which will show as slower performance or even corruption.
The spec above says to not have more than 16 in a chassis.
The reliability will manifest itself as 'how many times does a disk go bad'. Thus a better reliability will mean less RAID rebuilds due to a bad disk. During a rebuild, the system performance will suffer for the duration of the build, which will be hours/day depending on the size of the array.
Here is a link to a performance test of these types of drives: