I didn't end up going with the VNX. EMC's pricing is pretty steep and small upgrade storage costs were outrageous! I also read a lot of complaints about previous EMC devices that use the same technology as the VNX. My current Promise RAIDs run flawlessely so I don't need the added hassle of issues coming up with the VNX. I wanted to go with VNX NAS for better allocation and storage upgrades.
We are going to upgrade our current Promise RAIDs and stick with our current directly attached fibre setup. They are now offering 72TB @ $32K and 180TB @ $70K, this pricing is amazingly good. I think Promise is releasing a NAS system soon as well. You might want to look into that.
Apple recommends Promise and Active Storage units.
If you do use the VNX please let me know how everything goes.
I've migrated about 22TB of Data to the VNX successfully. It was pretty painless other than the increased complexity of the FC switch and VNX. We went from the infortrend attached to a small qlogic 1400 to the VNX 5300 doing block and file attached to a redundant brocade FC setup.
I'm not attaching to OS X servers though (I have Lion clients running SanMP). I imagine it would work just as well.