Hi Richard,
I just saw you ordered the Belles 150 to try out, too. Smart move, testing out as many different amps as you can in your home, for no or little cost and in your own system seems to me to be the best method I can think of to ensure you buy an amp you know you'll enjoy.
You're welcome for assisting you in your search but I actually enjoy trying to help others with their systems. I get to vicariously enjoy their system improvements without switching all those connecting cables around.
I know I tend to encourage people to give class D amps a try before buying anything else but not just because they provided such a significant upgrade in my system's performance but also because I think they offer the best bang for the buck.
Of course, I realize that class D amps aren't always the best solution for everyone. There are many good amps available that will provide very good sound quality in most people's systems. But I'm fairly certain that good quality class D amps will outperform the vast majority of class A/B currently available since they're smaller, lighter, run cooler, are more efficient, quieter, more detailed, lower in distortion, have better bass response, are more dynamic and usually cost less. I have heard a handful of very good class A/B amps that outperform some good quality class D amps, however, they're all quite expensive.
I would urge you to ignore amp type and just choose the amp that you determine performs the best and is within your budget.