input sensitivity

I don't understand input sensitivity. Is lower better, because it allows the full power to be transmitted to the speaker more easily? I understand there might be less volume control.
Unless you were using a preamp with a high output impedance, I think it's unlikely that that the input impedance differences between those amps are the reason they sounded different. (Input impedance is different from input sensitivity.) The Pass is much lower-powered than the other two and doesn't have the best bass but does have a rich midrange. Its low input impedance can be a mismatch with some tube preamps, theoretically at least.
Drubin, that's what I came away with from that experience. The preamp used in the comparison was the Blue Circle BC21 which uses two 6SN7 tubes. But despite the problems with my system, I sure liked that Aleph 3.