I have used a Gryphon Callisto 2200 on the Gallos with great result :o)
another to add is the Tact M2150 ... excellent control and soundstaging (improves on this already outstanding quality) ... not an easy amp to find but VERY good.
also the Joule Vamp integrated (100w/ch tube/mosfet hybrid)... have used this extensively with the Gallos to great result - also hard to find though.
Henryhk, sorry I can't be of much help in A-B comparisons as I haven't had those amps together in my system. My sense is that the Ayre is slightly softer sounding but I wouldn't take that to the bank. Plinius seems to be a quite matching sensitive as it has sounded great in some systems and too warm and slow in others. To throw one more integrated into the mix the NAD S300 was quite good and a used one might be a great buy. It is basically a rebadged Gryphon Tabu.
I'm not a huge fan of the Krell and I have some reservations as noted about Musical Fidelity products. The TACT and the Joule I haven't heard but all others candidates that have been suggested strike me as reasonable choices. A great deal is simply going to come down to individual taste. There simply aren't any bad integrateds in play here.