845 SET? deHavilland / Art Audio/et..al.

Any impressions on the deHavilland Aries and Art Audio Carissa? How do they compare? Comparable 845 based amps that should be considered? How do they compare with those mentioned? And finally, and thoughts on the difference in sound between the dH Aries monoblocks and the stereo IOS? My speakers are Merlin VSM-MXes, should that enter into the equation. Thanks.