We use a Chefman brand and have been quite happy with it for the past few years. Ours is an older model that didn't have a temperature knob, but I don't know where to find that one anymore.

We just hook it up to a $3 timer I got at Home Depot. We're in a house with granite counters now, but when we were in an apartment with the standard cheapy countertops the under-heat was never an issue.