For starters, the NetApp family of products are all NAS appliances. The DS8000 is a high-end enterprise storage array, comparable to the EMC Symmetrix and similar products. While the NetApp filers are often used to supply both storage to both NAS and SAN-attached hosts, the DS8000 is primarily a SAN array, designed to serve storge directly to other servers attached via FibreChannel, FiCON or ESCON.
The high-end NetApp filers scale to less than 100TB at RAID5; the DS8000 scales to almost 200TB.
In terms of support, availability, features and such, I’d suggest visiting the web pages of both companies and take a quick glance at the data sheets. You’ll find that features like snapshots, mirroring and long-distance replication are somewhat similiar, but the execution of each will differ greatly.
If you already have a SAN fabric that you’d like to use to connect many, many high-performance servers to a storage array, you’re probably looking at a product like the DS8000. If you already have an estasblished server/data center network and would like to connect many, many general-purpose servers to a storage array, you’re probably looking at a product like the NetApp filers.
As always, do you homework and see what features these products have that meet your needs. Hopefully, this will start some interesting discussions on NAS vs. SAN (the right tool for the right job, I always say!).