I haven't played with the penny stove. If you want to see if it's efficient, take a look at Standards For DIY Alcohol Stoves down at the bottom of my blog post. Just run your stove a few times, see how much alcohol it uses, and then compare your usage with that listed in the Standards.

Just as a general FYI, there are basically five types of alcohol stoves.
1) A plain open burner such as an "Altoid" burner, with or without fiberglass insulation (or pearlite or similar).
2) A ducted port or "chimney" stove like a Brasslite, 12-10, or FeatherFire.
3) A semi-presurized stove, which is the type in my blog post. These are also called "open jet" type stoves.
4) A pressurized stove with fully enclosed fuel. A penny stove is of this type. These are also called "closed jet" type stoves.
5) A wicked stove where some type of wicking material is used.

HJ