I would say that for a business that would also favor proper support in case of issues, it's better to go with a off-the-shelf product such as Synology, QNAP, or such. The reason being that they're a one stop shop for their own hardware. And you will be covered by some kind of warranty with an option to buy an extended one, or to sign a service contract. The downside of getting something like Synology now (as opposed to QNAP, Asustor, Thecus and so on), is that Synology is closing its garden somewhat - as in it's moving to require Synology certified Hard drives which will be the only ones to work with its NAS products. Currently its in effect in Synology Business and Enterprise products (which may or may not be the level of product you need) but it may also start to arrive at Home based products.
Xpenology may (or may not) always have the option to use any Hard drive, and also mix between them, but it relies on self built hardware most of the time.