I maintain 80 degree ambient temp with the RHP and 90 degree belly heat with the UTH. So... I use both. The expense isn't in the heat source, it's in the thermostat. I use Herpstat which seems to be universally regarded as one of the best, if not the best.

But on that subject I wouldn't take advice from me. There are many more experienced hobbiests on this forum who are better equipped to answer that question.