Horse for courses, I've never got on with modern cabs, I understand the efficiency and the benefits of the lower weights I've just never found one I'm happy with. I suppose I like a simplistic approach, if you want a B-15 buy a B-15 don't buy a class d with a modern cab and then wonder why you can only get close
If you want a big valve amp through an 8x10 sound best thing to buy is a big valve amp and an 8x10.
Tonal comparisons are hard as there are so many deciding factors, you will find the Matamp can be way more transparent than the Ampeg, but to me it's always been a case of Goldilocks where Matamp is Ah Just Right sorta thing I've never been able to put my finger on.