Khan is clearly one level higher in all the technical aspects than RAI Penta. Khan's sound signature is neutral and quite revealing, although Khan has good tolerance on poorly recorded tracks. RAI Penta's sound signature is rich and fuller sound with slightly recessed treble without compromising the resolution much. RAI is certainly warm sounding but not dark at all. As I said above, RAI can't match Khan's wide staging, revealing resolution, and excellent imaging and timber. However, I enjoy RAI for its relaxing laid back presentation with seducing mid range, which is perfect for Diana Krall and Melody Gardot kind of vocal tracks. The bass of Khan may occasionally feel a bit lacking in quantity. But it's tight and accurate and extends very well to sub bass level. Khan's bass quality is excellent to my eats. Bass on RAI is more in quantity but a little loose, which contributes to its warm and relaxing signature. Both of my Khan and RAI Penta are still under burning in period. So please take my impression as a grain of salt. YMMV.