D’Agostino Momentum stereo vs D’Agostino Progression Stereo Amp

They are both good choices.....If I were you, I will contact my dealer to bring both amps for in-home audition. 

At this level of investment, you want to hear the amp with your upstream components and speakers and not quite make an decision based on other folks experiences and opinions. 

The dealer in question should then have to possess both models, and offer the momentum at secondhand prices🙄

Looks like your dealer can’t afford you the flexibility of audition. If you are buying a new amp from a dealer, he should provide you the full service, i.e. in-home or store demo of the amps you’re willing to buy. If he is not capable of providing you full service then I would look at another brand. 

If you buy used Agostino amp then you’re assuming all the risk. If you like it, you keep the amp and if you don’t then resell it. 

I am sorry but if I am spending $35K - $22K, I would want to hear that amp first before purchase. 

The top of the line Luxman's do not do too shabby either. :)