I did once measure the value of the Kneen and the Quight. This confirmed what I had also observed in divegring short-range leapers: roughly 2/3 of the value of a piece is determined by its captures, 1/3 by its non-captures. The value of the Quight was thus about 5, and that of the Kneen about 7 Pawns, in a FIDE context.
I did observe an interesting irregularity, though: testing divergent compounds of Knight and Commoner, which themselves test as nearly equal in value, the combination mNcK (Kning?) proved to be about half a Pawn stronger than the other combinations. I suspect that there are some penalties and bonuses on the move pattern as a whole, which happen to cancel each other, so that its value is in the end not much different from that of other 8-target leapers. The K move set is very poor on 'speed', but very good on 'concentration' (i.e. lots of orthogonal contacts between the target squares). Speed seems to be mainly important on non-captures, determining how many turns you will need to reach the location where you are needed (such as a promotion square). Concentration seems to be mainly important for captures, determining whether you can attack Pawns in such a way that they cannot simply move away, and whether the piece has mating potential. The Kning thus has the best of both worlds: the Knight move provides the speed, and the King captures the concentration.
I did once measure the value of the Kneen and the Quight. This confirmed what I had also observed in divegring short-range leapers: roughly 2/3 of the value of a piece is determined by its captures, 1/3 by its non-captures. The value of the Quight was thus about 5, and that of the Kneen about 7 Pawns, in a FIDE context.
I did observe an interesting irregularity, though: testing divergent compounds of Knight and Commoner, which themselves test as nearly equal in value, the combination mNcK (Kning?) proved to be about half a Pawn stronger than the other combinations. I suspect that there are some penalties and bonuses on the move pattern as a whole, which happen to cancel each other, so that its value is in the end not much different from that of other 8-target leapers. The K move set is very poor on 'speed', but very good on 'concentration' (i.e. lots of orthogonal contacts between the target squares). Speed seems to be mainly important on non-captures, determining how many turns you will need to reach the location where you are needed (such as a promotion square). Concentration seems to be mainly important for captures, determining whether you can attack Pawns in such a way that they cannot simply move away, and whether the piece has mating potential. The Kning thus has the best of both worlds: the Knight move provides the speed, and the King captures the concentration.