Hey, Kyle (a very fine name, BTW). I've got to go with thebigspendur and LX_Emergency on this one. Provided that you've not used cold water to make the lather, there is not a noticeable change in performance. While I've not used the Moss Scuttle, I've tried many other tricks for retaining lather heat. At best, I believe it can add to the luxury of the moment, but does not really effect the quality.

Having said all of this, every man's shave is a very unique and individual experience and if heated lather does it for you, then by all means heat it up, my good man.

One word of warning about the mug warmers; I have seen reports where the device heated the mug to a degree that the tips of the brush (badger) were slightly damaged.