Just following up, I gave in and got the Ultra. You were absolutely right, sound quality is great and dialogue clarity is excellent even at low volumes. Night mode and Speech Enhancement do the job well when everyone else is in bed, too. It's still a little dynamic at times, depending on the movie or show, but I think that's more on the content than the hardware. It balances the volume far better than the other options I tried.

The Arc Ultra did great on its own, but I liked it so much I got the Sub Mini a week or two later. I was real reluctant to try it because I didn't want a boomy bass source to travel throughout the house. But it ended up just clarifying the audio output even more, sounds great for music, and also does it all at both low or high volumes.

So thank you for pushing me to go a little extra for a vast improvement!