100% no insult taken, My use case was to find the fastest setup possible for the best price. It definitely didn't start with me looking at windows, it truly started with zol and open stack and then progressed extremely slow for almost a year and half while I figured out how file systems and storage stacks and networking all worked together. Then one day storage spaces and rdma smb 3.0 was brought to my attention and as it turned out it was easier to use, its networking was much faster, and once I understood how it worked and what parts were the weak links I could account for that in my setup and create a setup in which the bottle neck was the cpu (imagine that, not a raid card, not ram, not drives, not network, but the cpu!).Please don't take this as a shot at yourself as you clearly know plenty about SS, the above are nice benchmarks but really, screams, poor use of money. If you had enough coins for all those NVME drives and SSD's wich both have same limits of space compared to Spinners, then a Hardware RAID card would found its way in there long ago. SS still sucks, it is not suited to production environments and especially where VM's are concerned.
I use it because I have around 50TB hanging off it. It suits me well and the average files I am moving are around 1-10GB which move fine, even when it fill the RAM and then falls back to drive write speeds of 60 odd MB/sec (8x drive, double parity ReFS) for one array and the same style array with just single parity is 15MB/sec faster. The speeds when these were NTFS were only less than 5MB/sec different.
I won't bother with the arguments around how much of a pain in the arse SS is to use when it decides to have a shit in its pants. If I had coins for either a HW RAID card or more drives (need transfer space) then I would go HW or ZFS.
I will say that with parity raid types you maybe right, a raid card may be faster. But currently have a 24 disk 17 column storage space (17column is the max size of a dual parity space) with 3 400gb ssds as journals and it works great. Not nearly as fast as the mirrored arrays with storage spaces but good enough for the 100tb + of space I am using and sequential speeds are extremely fast.
As for poor use of money I disagree, storage spaces has its draw backs for sure but as performance goes it scales well beyond what a single raid controller can handle in certain configurations and that's where the catch is. Yes dual parity and single parity spaces may be slower than a raid 6 or 5 on a proper raid card after storage spaces uses its write back cache. But those layouts are not meant for production vm workloads but for back ups, digital media type archives, or for most home server tasks (Microsoft expresses this sentiment many times when describing storage spaces).
With that said find me a raid card that can hit 2 million iops in any configuration? I used 3 x 9300-16e hba with 48 x 256gb ssds and total cost was ~$5200. This was a little over a year ago and prices have changed, but I couldn't hit those numbers any cheaper and couldn't touch those performance number using raid cards let alone at that price.
I have moved over to nvme drives for fun after selling off some of this equipment and am very impressed with this technology. It actually cost me a lot less to hit these performance numbers using nvme drives. It was a win win changing over to nvme, cheaper and faster.
The fact is I really like zfs and would prefer to use it (I hope refs can raise up to that level at some point, but i am using ntfs since refs was dramatically slower in server 2012 r2 when i was benchmarking with all solid state storage)but the networking stacks for both Linux and bsd are far to slow to utilize the full speed of the file systems using a file based shares. If my use case was utilizing block based storage more than file based then I could spend the time compiling rdma network storage tools for Linux and bsd and get the best of both worlds but as it stands right now windows has the best of both worlds as long as I am willing to use mirrored spaces for my production workloads and don't mind the that my dual parity spaces can not sustain multiple 100,000s iops (but my sequential speeds are that of 17 columns/hdds). Along with that I would prefer not to spend my time compiling and tweaking these rdma based tools when I can spend $20 on a connectx2 vpi card hit 3.2 gigabytes per second per card and have smb 3.0 rdma scale every time I add a card. So with that I believe it comes down to the fact that if performance and cost are top concerns then storage spaces is the best way to go.