Considering you are in the enviable position of having heard both speakers, could you elaborate a little more on why you think the Devore's may be a better match. Specwise, they look similar except that the Gibbon's go down lower. I think the thing that has me leaning towards the Harbeths is the descriptions I have read about the tonal balance. The CS300X is a bit tilted up in the mids and treble region, especially with the Sovtek tubes. I have read that the Harbeth's are bit more subdued in those regions. In addition, they do not seem to be picky about what they are connected to - although I have also read they seem to like lots of SS power. The Gibbon's seem to be more picky and can sound overly bright with the wrong components or setup - or so I have read. On the other hand, the designer seems to be a tube guy so there might be more synergy with tube amps. I'd be really interested in your thoughts on the two speakers and I would also like to know what amps you have tried with them.