New ReadyNAS purchase decision

I've stuck with ReadyNAS for personal use since before Netgear acquired it.  I likely would go another direction (though I don't know what, since I'm not in the market) for a business system.

One of the big mistakes many people make is to initially fill the NAS with drives, which it sounds like you are thinking of doing (again?).  There are a coupe reasons to not do that.  One is that all the drives will be of the same age, and may die nearly simultaneously.  There is a bigger risk of a second drive failure when re-syncing a replacement.  The other is cost of expansion.  If you had started with 3 x 8TB to start with (which may not have been an option then, it's just an example), then you could significantly increate your space just by adding more 8TB (or larger) instead of having to replace them all.  For the best bang for the buck over the long haul, start with the smallest number you need of the largest drive you can afford (really new larger ones tend to not be cost effective, but last year's "bigger & better" often is).to meet your storage needs.  Then, you can add drives instead of replace to expand.