To be honest I don't get all this moaning and groaning about Time Machine and Fusion Drive.
I was also a pro thinking that I can do all better manually until I had to take the responsibility for not only my data but also the data of my family members, employees and some hundreds of additional users.
In the following I want to provide some experience, excluding enterprise SAN solution because they are out of reach for most users and SMB customers.
I use Time Machine for Macs and the "equivalent" on Windows through external RAID drives hooked to the servers and didn't loose any data in the past years.
This doesn't mean that there were no issues but most of them can be avoided with some foresight.
First to drive failures. I normally replace drives in servers, hard pressed workstations or storage systems every three years. For normal clients I have defined a five year lifespan.
The replacement cycle of 3,5,6 years is also necessary to cover the average data growth between 200 % and 300 % in three years in my case.
In the past six years I had three failed drives, one in a RAID (bad production batch- RAID rebuild failed), one mobile drive (shock destruction) and one SSD (early model with weak controller firmware). All these issues were solved with Time Machine.
In addition I use it for the case users accidentally wipe or overwrite files or discover after weeks that the earlier version was much better.
In order to hold enough versions I use backup volumes with one and a half up to four times the space the device has. So Time Machine is a huge time saver and covers most of the common issues with the benefit that switching a Mac is also pretty painless especially because it's possible to clone TM-volumes and you can add e.g. a second backup volume for the same data at another location.
Of course there are some scenarios Time Machine (or similar solutions) doesn't cover and you need additional failover and backup scenarios in place. I just name a few I had in the past. Examples are a crashed SQL database, an ill running Exchange Server stumbling because of incompatibilities between the service pack and third party components, a defect distributed Active directory after a failed schema update and much more. In addition you might have to consider some additional backups at another location for cases like flood, fire, earth quakes etc.
Now some words to Fusion Drive. I think it also covers a specific but pretty common scenario.
I use mainly an i7 MBP with 256 GB SSD and an i7 iMac with 256 GB SSD and 1TB hdd.
I'm an early adopter of SSDs using them since 2008 and I'd never ever consider to go back to an hdd only equipped Mac.
The problem is that switching to SSD breaks the doubling space in two years scenario which was a huge pain in the a** for me. I have constantly to manage my files on the MBP because both volumes (Bootcamp and OSX) are getting out of space.
I have the same problem with the iMac. First it was OK to put some rarely used libraries and virtual machines on the hdd but by the time I got really annoyed by this time wasting actions.
In my opinion FD is the best solution for the common user wanting SSD speed but don't want's to go through all the hassles necessary fighting the "data growth cycle". It's a hands off solution and combined with Time Machine backups It should cover > 90 % of their needs.
I'm currently testing Fusion Drive and I can't wait to switch to it in order to skip the nasty data management obstacles preventing users from enjoying SSD speed. I don't care whether there will be cheaper, better SSDs in five years.
I want the performance and space now. In addition I'm sure that until then I'll need a three TB SSD.
It's more likely this will be a three or four TB Fusion Drive then.