My feeling is that neither the 60W amp nor the 150W integrated are powerful enough, considering the 500W capability of your speakers, your very large room dimensions, and your interest in music that has wide dynamic range.
If I were you I would try to audition one of the higher powered X.5 (class A/B) amps, as your target selection, and compare its sound with the XA200.5 (pure class A), which I suspect is well out of your price range. Assess how much difference, if any, you can perceive between the sliding class A/B design and the pure class A. I suspect it may be small enough that you will feel comfortable choosing one of the X.5 amps, which provide more watts/dollar, as well as functioning less like space heaters.
To answer your specific question, no I don't think that a 200W pure class A amp is necessarily better sounding than a similarly designed 60W pure class A amp, other than, of course, on high volume peaks that approach or exceed the power rating of the smaller amp.
Regards,
-- Al
If I were you I would try to audition one of the higher powered X.5 (class A/B) amps, as your target selection, and compare its sound with the XA200.5 (pure class A), which I suspect is well out of your price range. Assess how much difference, if any, you can perceive between the sliding class A/B design and the pure class A. I suspect it may be small enough that you will feel comfortable choosing one of the X.5 amps, which provide more watts/dollar, as well as functioning less like space heaters.
To answer your specific question, no I don't think that a 200W pure class A amp is necessarily better sounding than a similarly designed 60W pure class A amp, other than, of course, on high volume peaks that approach or exceed the power rating of the smaller amp.
Regards,
-- Al