What type of environment are you looking at implementing? Wintel? Linux? Unix? All the above and others?
What are your storage requirements:
a) What kind of performance do you need for your host(s)? If you are using clustering and/or a clustered file system, you will want a solid, robust I/O and throughput advantage.
b) What are your useable storage capacity requirements now? In six months? In a year and then two and three years from now?
c) Do you need path failover?
d) What kind of e-mail solution are you using/planning to use?
e) Will any other applications or file servers be using the storage as well (i.e. will you be consolidating server storage, implementing a SAN)?
f) Are you implementing a SAN or direct attach?
g) What kind of high availability requirements do you have? Do you need 99.999% uptime or business hour uptime?
h) How do you plan on backing it up?
Bottom line: see if they will allow you to evaluate them before buying. This would be the best way to compare each and see which is best for your application.
If you can't do this, and you need to make an informed decision based on the ton of information from the sales and marketing firehoses from whatever vendor -- click here for a more expanded five point checklist. This is something that I found very nicely done by someone in a previous SearchStorage.com discussion. I've added to/modified it, and it may prove useful.
This was first published in April 2003