Autometer owns Stack, so the new stuff is all using good quality Stack internals.
Auto Gauge, different matter. Not bad, but not as good as Autometer.
I've got all Stack gear in mine, which I'm really happy with. Not cheap though.
TIM gauges aren't bad, ok for watching for consistency and they match the original instruments well. Cheap too. I used to have a TIM boost gauge in mine, and it seems on reflection that it was fairly accurate.