It's out! The news you were waiting for! It's not from the Feds, since they gave up on thermostats three years ago, finding them too difficult to test! Some independent agency did it, and it's still a mystery:
User friendly thermostats report
Venstar(top three) & Nest(top three?) are mentioned, but who are the others? Is Lux at the top, again? Why must we pay for timely information that should be free? Is anyone else out there testing thermostats, or are all of us just "testing" condensers? Can any do dual fuel? Outside temperature? Inquiring minds are dying to know!