So I’ve been running it on 3 of my machines now. Two of them have a single 6TB HDD caching to a partition on NVME SSD, and the other has 4x 10 year old 2TB 7.2K rpm HDDs in RAID0 caching to a NVME partition.
My experience and opinion up to this point hasn’t changed. First launch of games is about what you’d expect, and the RAID disks aren’t really much faster than the single 6TB WD black, which is amusing.
Subsequent launches *feel* like an SSD though, and this is maintained as long as you aren’t loading a level or part of a world for the first time. I also have write caching to RAM enabled on my 64GB machines, and the big steam updates are noticeably better.
I’m a niche user though, my steam library alone at this point is approaching 5TB and that’s not that crazy as I’ve seen WAY bigger. As a matter of convenience, I keep all games installed. It’s just not economical to use an SSD, and I can’t be bothered to move the better part of 100GB over to the SSD when I get sucked into a game I haven’t played in a while.
I have a VM spun up on my unRAID server that keeps a local copy of my steam library updated, as well as snapshots of my machines; if my RAID or Primocache take a dump it’s a minor inconvenience at worst.
This is pretty close to the ideal use case I think. SSDs are so cheap these days that I can see this type of software eventually becoming irrelevant, but for now it is very useful and provides meaningful benefits in specific scenarios. They have a trial period for a reason, so give it a try before bashing it.