I actually felt I gained a bit of dynamics and mid-bass slam going to the ATI signature. My proceed was aging though and could’ve benefitted from a cap replacement. Regardless, it gave nothing up to the proceed.
The proceeds are indeed repairable. There are replacement channel modules available that when replaced will buy 15 more years of service. Pyramid Audio in Austin, TX can handle any repairs you may need. The proceeds are a great value at their selling prices.
Theta may be good, but they’re Uber-expensive. If you’re mainly HT I bet you’d never hear the difference. Save your money. I still prefer to stay with class A/B gear and decided to go with the ATI signature. No regrets!
Best wishes in your search and I hope you’re happy with your final decision.