i need a nas for a small business and don't yet understand what would be best

[Enquiries]

i am looking for a recommendation on a nas for a small print shop. the editing station loads the print or cut file to the server than the respective station pulls the respective files. we have a network in place but need to upgrade the server system and a nas seemed like the best budget friendly option. the files are not individually that large (normally less than 1.5gb) but the boss wants longish term storage on the nas.
security and being able to assign differing levels of file access to each device is important. and the ability to monitor the server is also quite important