I Used to own a pair of 5As and have heard them with the number of different amps in my listening room including BAT 75se, Blue Circle AG8000 and BC 2.1, Atma-sphere, JC-1s and Conrad Johnson 12s. They are great speakers and you pretty much get out of them what you put into them. With the BATs, 2.1s, and to a lesser extent CJ 12s they were lovely. (For Jeff Jones, they sounded big, dynamic, and maybe just a little dark with 75se and VK5se amplification - very seductive). With the big Blue Circle's and atma-spheres, they sounded very clean and clear. My favorite is the 2.1s... just beautiful (they don't get much press anymore but I think they are terrific amps for the right owner).
As far as bass response and playing loudly, They don't take much power to play at what I think are reasonable levels, but can really suck up the Watts quickly if you want to play loud. Some people say that speakers with first order crossovers cannot play that loud but they played plenty loud for me (using the JC-1s). I think your bass response will be dominated more by your room than by your amplifier, although the big Blue Circle and Parasound amps had the best bass (no surprise)
As far as bass response and playing loudly, They don't take much power to play at what I think are reasonable levels, but can really suck up the Watts quickly if you want to play loud. Some people say that speakers with first order crossovers cannot play that loud but they played plenty loud for me (using the JC-1s). I think your bass response will be dominated more by your room than by your amplifier, although the big Blue Circle and Parasound amps had the best bass (no surprise)