I have a 180* drilled that is used during the summer and a 195* non drilled for winter. The 180* drilled takes forever to get up to temp in the winter. Drilling a t-stat is equivalent to the t-stat being partially open when it would normally be closed. I've ordered a 180* non drilled to try out for all seaon use.

A little off topic, but since the OP question has been answered, I thought this may be be helpful, in the event someone does a search later for "which thermostat".