Looking for a reliable machine to be on 24/7 and last 5years+, mostly as desktop. So really looking for ECC support.
Ryzen looks potentially an option with unofficial ECC support. There is a Lenovo SFF in Australia with this, not sure if the board supports ECC though. IdeaCentre 720 doesn't look available here.
Perhaps one of the cheap HP deals and upgrade the E3 Xeon?
Run a few low-power supermicro Xeon-Ds but they are mostly for VMs and single-core performance is not ideal.