Looks like there's a lot of users here whom enjoys ZorinOS, and that's great! 
Had I known it before Mint (don't think it was around or known well then), may be running it myself.
I have storage wise A 1Tb WD green, 2x 1.5 Tb WD green, 3 TB seagate, 1.5 Tb Samsung wireless media drive, caddy I can stick some of my old drives in A 500/320 or 2x 250 Gb and 4x fujitsu SAS cheetah's witch were raid striped as my old boot drive before switching to SSD.
Ian, that's a massive collection of backup drives you have there.....well over 2x what I have in 4TiB total, two 1TiB Samsung HD103SJ's (many regarded as better than Caviar Black of the same specs), a 1TiB WD Caviar Black, and two 2.5" 500GiB backup drives, one a Hitachi, the other a Seagate, all SATA ll. Also have a 500GiB WD RE4 in my main PC, which I was using for quick backups, until all of these "crypto" infections came along, after that, it became a Data drive to the three SSD's, and also have my Linux Mint /home & Swap partitions (the root partition is on a SSD).
Was tempted to grab a 4TiB WD Backup drive on promo for $119, and here's the reason I didn't. The negative reviews by far outweighed the positives, and at that price for the space, it just looked too good to be true. Maybe it was the cheap enclosure, but if it's cracked open, there goes the warranty. My guess is that it's a drive they came out with, didn't perform or sell well & repackaged as a backup drive. Rarely though, have I seen these fail, normally it's the cheap connectors in the enclosures, which are plastic & retains heat bad. Half of the negative reviewers reported bad sectors from the go.
I prefer to use a docking station anyway, if a backup is going to take awhile, such as the internal RE4, can place a fan close to the drive if it's getting more than warm to the touch.
Oh, and I almost forgot, do have a 1TiB Seagate (SATA lll), however it shipped with my Dell PC & will have to leave as is until the warranty expires in September 2017. Then will make a backup drive out of it too. Actually that drive is 3 egg rated on Newegg, with high failure rates, maybe it was for the best I got it out of my PC.
I doubt I'll catch up with you on storage any time soon!. 
And (dare I incur the wrath of my good mate Cat?) - in many ways I would call it more of a dropin replacement for Windows XP/Windows 7 users than even Linux Mint Mate.
That may be so, and to be fair, there has been reviewers of ZorinOS on sites there open source is at least somewhat promoted, who stated the same. Linux Mint isn't the "only" drop in replacement for Windows, just the most popular for now. A large majority of Linux Mint users came straight from Windows, many others are defectors from Ubuntu when they went with the Unity desktop, which was very unpopular at release, don't know about now.
Everyone has their right to opinion here, as well as choice of Linux distro, and that I want to make clear.
I'd much rather seeing folks running Zorin over XP & Vista, and their computers, if possible, would thank them for the less strain on components. Especially those coming from Vista, the OS should have been named "Bigfoot", had it once on my second best computer, a MSI notebook (specs in my sig below), and it weighed it down. Very seldom did it use less than 4GB RAM, and CPU usage would always be hitting 60-80%, and idle at 20%. Can't imagine the strain it placed on the computers it was built to run on.
Anything to get folks off of these insecure (or heavyweight) OS's, I'm all for! 
Cat