I agree with you that the biggest component between your source and your ears is your room and that room acoustics get really shoddy consideration in audio, considering how important they are! What I mean, and this is for you too, Ethan, is that the "good science" is the theoretical principles of psychoacoustics as previously tested, proven in many designs over millenia now (resonance for example), and well written up. I find that, though the formulae are dense for my level of interest, the Master Handbook of Acoustics does a very good job on explaining all this based on real research. And it isn't the only source that the more knowledgable than I can cite for you, just the one that worked best for me.
I don't mean to imply that a manufacturer's claims, nor the anecdotal experience of various listeners/tweakers is "good science", but it does tell you something about subjective experience. Don't discount subjective experience completely, as most of "hearing" is not in your ear but in the perceptual processes of your brain.
Soooo, the room lenses' theoretical functions are indeed well known, even if the manufacturer is spreading it thick or the listeners are unable to identify those principals properly. I think David did a great job of condensing most of it for you, but Jon Risch also wrote it up well here for me years ago. These are primarily diffusers of a curved design, very secondarily diffractors, minimally resonators and absorbers. However, the persistence of demonstrations of various similar diffusor designs suggests that this is a correct formulation of the operative hierarchy (a la JR). As to how much the 4 process synergy contributes to the overall impression, your guess is as good as mine.
The reason, Ethan, that you see them all over the place has to do with the differences in the reflective patterns of our different shaped and filled rooms, as well as the radiation pattern of sound from our different speakers.
I cannot tell you that these are the singularly most effective devices on the planet; our rooms are too idiosyncratic for any device to prove such a claim. But I can tell you that they do work, they do work differently in different positions and in different rooms. And because they are not primarily absorbers, they don't work in the same way as absorbent panels do, though you could move around the absorbers and get some variation in effect as well.
Try them out and see for yourself. They're very cheap and easy to DIY.
