First foray into separate 2-channel amp, 200wpc

Hi, I am thinking of purchasing my first powerful 2-channel amp, to use with my Yamaha RX-V1800 receiver. This is kind of an experiment, so I don't want to spend a fortune. I need to see if a powerful amp will take better control than the Yamaha of my Monitor Audio Silver 9i speakers I just picked up. I am thinking of a minimum of 200 watts/channel. I am looking at spending up to around $500. I will probably want to find something used here on Agon.

So far, I am most drawn to an Adcom GFA 5500 here on Agon, although I am aware there are many other brands in that level of amp. I am aware of Emotiva, and wonder if anybody feels a new or newish Emotiva will be better in any significant way than the 5500. This will need to be a good performer on both music and movies.

Or, since the Yamaha is fairly powerful for a receiver, is there a likelihood that the Adcom of something similar will not make a detectable improvement?

Any other suggestions? Thanks.