The schism/stepping off point is (or seems to be) cost. For the cost of 10TB of BestBuy class NAS boxes one could easily just get a refurbished commercial server that will always have parts available, is designed to take 100+ times the beating you'll ever give it, and it has a proper true hardware RAID controller ... With a year warranty ... For roughly the same price.
-Stoic Joker
The running cost, the noise, the heat, the storage space... all for just 10TB in a home storage context? Hardly worth it IMHO.
I'm going OT a bit to look at this from another perspective,
do we really need the "redundancy and high availability" for this kind of usage? I used to deploy RAID 10, get my AV content carefully ripped, well organized, double-checked for corruption... only to have the majority of content replaced in less than a year due to newer releases which entail better content, higher definition, 2D->3D, etc.
Take
Avatar (2009) for example (I assume most of you have watched it by now), I had over 150GB data turnover on this particular title alone.
1. Avatar BD
1080p - Ripped, organized, verified, gave away and removed from storage.
2. Avatar BD
3D 1080p - Ripped, organized, verified, gave away and removed from storage.
3. Avatar Extended Collector's Edition
1080p - Ripped, organized, verified, gave away and removed from storage.
4. Avatar Extended Collector's Edition
3D 1080p - Ripped, organized, verified, currently in use, hopefully it'll last another year or so before they re-master it to go beyond 1080p.
Same theory applies to audio as well, at least in the genres that I listen to (DTS Master HD soundtracks and classics).
Thus there's not much reason to spend so much money and effort to have HA storage in the home media context. :) The content is disposable and is likely to be phased out before you have a clue.