Terrablock upgrades or jump ship to MetaSAN?

Our 8Tb 24D Terrablock is 5 years old now. It has worked flawlessly and successfully recovered from drive failures, multiple times. I like that it’s a low maintenance solution. File level was never an issue until we installed CAT DV.
Through a creative workflow, we’re able to get CAT DV to work, but it would be nice to have file level access. That’s a $7k upgrade. I need more nearline storage too, another $8k.

For the same price, I could go with MetaSAN. Use our existing XServe and fiber cards and buy a 32tb RAID. That would give me a file level solution for CAT DV, give me more nearline and turn it into online, give me more SAN space as well as space for weekly SAN backups (which I currently do not do).

How well does MetaSAN work? Can I expect to go from Terrablock to MetaSAN without much headache or am better off staying with our older, but solid system.

Thanks,
-dMR