I think, the Keilidhs are quite sensitive regarding the amp. When I bought them long ago, I tried several different amps in the shop for hours. I heared them with Yamaha and Denon consumer grade amps - and that was awfull. A Harman-Kardon Receiver did the job then much better and right now, I have them connected to an old Harman Kardon PM655Vxi amp, which gave a real boost to the Keilidh's bass.
Just like will1960's choice of music, I mostly listen to acoustic music (voices, paino, folk, smaller classical ensembles, jazz), but they do well with my occassional Led Zep or Queen cd as well.
The Keilidh's strength, I think, is there neutrality. Some people may consider that boring, but for natural sound, they are hard to beat in their price range and small size.