Hi TommyT. Two great British loudspeaker manufacturers to choose from if I may say so. I enjoy both but this is down to two things really, personal taste and your partnering equipment. What amp will you be using to drive your prefered speakers? This is a biggie as they are quite different in terms or driving requirements. The ATC will demand much more from an amplifier than the Spendors in terms of pure power and control, but I think it is fair to say that both enjoy having an amp of quality preceeding them. I always find the ATC a bit fussier in terms of amplifier choice as when driven properly are incredibly revealing, but when not, end up being a little bit shouty. The Spendors actually have a better frequency response but I typically find them more even handed across the bandwidth. Have you tried either pair out with your own amp? If not and you would like to hear the Spendors (I do not have the ATC) drop me a line and Icould sort this out for you. I'm in Central London if that works for you.