Thoughts on xServe RAID replacement?

Hi everyone. Thanks for reading.

I am replacing an aging xServe RAID in a clients network. They currently use the xServe RAID as storage for their mobile home folders, company file shares (RAID 5 w/ 500GB storage), mailstore (RAID 1 w/ 250GB storage) and backup for other servers (RAID 5 w/ 3TB storage). This is hooked up directly via FC to an Intel xServe running 10.6.8 server. They would like to replace this simply because they need more storage for files, and the age (about 7 to 8 years old).

I would still use the existing xServe RAID as backup storage, however, we are looking for replacements. Right now I am pricing out a Promise VTrak E-Class with 8TB of storage (most likely will go RAID 10, so 4TB of useable storage) and a new 4Gbs quad fiber card. Total for both is around $8500. I am not convinced however they need that fast of storage for their use. They can get a Drobo 800i (bear with me here) with 8TB of storage (if dual drive redundancy is on the useable is around 3.6TB) and a dual 1GB PCI ethernet card for around $4300. In the past, we have only used the DroboPro, and think that particular unit is too slow for anything but archival data or backup. We have yet to use the 800i (nor the 1200i).

What does everyone think? Or is there another product we should also be looking at? Network is 1GB for around 40 users. Mobile accounts just sync at logoff, and useage of file shares is probably light to medium.

Thanks again.