Thanks for the prompt reply. I totally appreciate the implementation differences; it was only meant as a functionality comparison
The problem with the file placement rules (as I understand them) is that I would have to set up the SSD as a "replacement" for one of my archive drives and not as a proper cache. To explain my use-case in more detail: I have two 3TB "archive" drives with pool-level duplication enabled. I added an SSD to the pool as SSD-type via the SSD Optimizer Balancer plug-in. In order to have a file/folder go to the SSD, I have to uncheck one of the Archive drives so it will use the SSD as the duplication.