We have to use NAS...
We use NAS for development and for some of our production systems. It is fine for some things, but because NAS is independant from the server, it has to have its own downtime for upgrade and repair, which will affect the production servers. If you have available downtime, then it shouldn't be a problem. IF you have 24x7 requirements, I would be very cautious. Heavily invest your time in appropriately planning the layout of the volumes!
You should be on a gigabit core, too.
Make The Choice!
Accept The Consequences!
Deal With The Results! "