The feet tapping is certainly a good criterion for judging.
Regarding the Spendors, I only want to add that I owned SP1/2's for a couple of years and a friend of mine had the FL9, so I wasn't shooting from the hip. Except that my experience with the Thiels has been limited. But my experience has been that they are champs when it comes to image specificity, which I never found to be true of Spendor (or many other speakers).
I'm sorry to say that I never really "got" what all the fuss is about Spendor. And I owned original Quads for 15 years, so it's not like I'm coming from a Cerwin-Vega heritage or anything. And I do know the sound of live music. I guess my musical priorities are different from the legions of audiphiles who admire Spendor.