I'd have to read the specs to give a detailed answer; but I DO want a PID with a switched OT1, not mechanical relays. It's a longevity issue because a PID'd espresso machines OT1 will be switched on/off thousands of times per day, and a switches lifetime is measured in millions of on/off cycles, versus a relay which has a much shorter life expectancy. The OT2 output can be a relay because I just use it to control steam temps.
Then consider quality: The Watlow, Cal, Fuji controllers are made under very tight QC standards - the cheap stuff from 3rd world countries aren't. I buy the more expensive units (mostly used) because I don't ever want one of my machines to fail because I cut corners on the controller.
Other than that, there's documentation to consider. Have you ever read Chinese that's been auto-translated? Those manuals are a joke!
