I believe I have mine set to come on at 3.5 and off at 2.5. I like my beer cold, but I didn't want to risk it getting below freezing in the bottom of the keezer (my probe is in a bottle of water on the hump). I left the compressor delay at the default, because my cycle time is long anyway.
If it's on a porch, I would watch closely for areas of condensation this summer and seal those air gaps. It will run a lot in the summer, and if your area stays below freezing for long periods, you may need to use the heat side of the controller as well!