Hi Stephen, like Antony D, I moved from CDX2/XPS to NDX/XPS (also in 2014). My NAS is a Synology with WD Red HDD's. I also rip with dBpoweramp but although most purchases are downloads, dBpoweramp is an excellent metadata editor for these.
Getting your head around this is quite simple, but too many advisors can make it confusing, I advise to spend time with a dealer or possibly better with a person who has a system who is willing to spend time with you to explain it & answer questions. I've done it that way for others twice now, a couple of hours with the bits & wires in view all works well. I see HH asked the question about you living near Portsmouth, but if you are nearer Oxford you are very welcome to my system.