Hi Val,
I am using a Primaluna Prologue Two tube integrated that has, I think, similar ratings to the Cary and it is a great match. The Sapphire XLs are by no means a dark/dull speaker - I think that the response measurements in the XL review linked at the top of the page bears that out.
They are highly revealing, but not artificially bright. When comparing the sound of the XLs powered by the PrimaLuna to a solid state amp, I hear what I would expect, the tube amp is a bit warmer and more musical and the solid state is a bit more analytical. I think that Mike also has direct experience with this as he has used the Prologue Two with the XLs at trade shows and gotten very good results.