Considering a herpstat 2: Opinions / Sources?

[The Serpent Merchant]

What Eric Alan said is spot on.

The last point there, and I could be wrong, is the most important.

When a Herpstat fails, something about the way it's wired means it always fails in the OFF position. Other thermostats fail in the ON position. This pretty much eliminates the need for a failsafe secondary tstat. Perhaps the other manufacturers are doing the same now, but this was the case a while back and was pivotal in my own decision after reading threads about the horror of thermostats failing in the ON position.

They have a relay (electronically operated switch) that in the case of a failure physically cuts power to the outputs. According to the RBI website the VE line of thermostat now have this too, but I'm not sure exactly how their software deals with it.

At the end of the day the Herpstat 2 and the VE-300 x2 cost the same, but the Herpstat 2 is a much better/versatile unit.