With all due respect to all involved, B&K is further "up" the scale - as you indicate. I don't believe this is a current model, but you might want to check with B&K directly. The name is not the only impetus, as this company is not mass market, as Onkyo aims to play in. Their designs are on par with some serious amplifier companies.
Their products are designed to be driven, and are very solid and are extremely stable driving difficult loads (speakers). I have a close fiend using the ST55 to drive Totem Mani 2's - which are notoriously difficult speakers - and it performs flawlessly.
As you have stated, the cost may not be worth it to you. The Onkyo is working well for you, and I would venture to say would continue to do so. Depending on your setup, and future thoughts to upgrade, this could be a good time to start positioning any purchases with the future in mind.
However, only you can determine the best path for you and your family.
I apologize for not remembering your setup.......
