Someone recently told me that in their experience, in general, that the higher the db sensitivity of a given speaker, the more you sacrifice in terms of sound. In other words, lower db rated speakers [ 86-88 ] typically sound better. Any thoughts on this?
Yes this is true. This matches my experience with conventional box speakers. As generalizations go, this is actually quite a good rule of thumb (there are exceptions).
The light weight and rigid diaphragm structures necessary to produce very high efficiencies (ceramic, metal etc.) generally result in an under damped system (high Q - resonances). Furthermore, the highest efficiencies are often achieved by using a long voice coil in short magnetic gap which means the linear operating range of the driver excursion is modest and it is less efficient at dissipating heat than a short coil mounted in a more expensive massive magnet assembly; this results in more distortion and compression at modest SPL's and the speaker will sound positively dull and boomy at high SPL's.
I haven't mentioned horns here, all I will say is that I have seen plenty of horns used for sound reinforcement but rarely, if ever, have I seen a horn used as a professional studio monitor; this fact alone speaks volumes about the fidelity of high efficiency horns...