Advice Please... CA300 vs A21

I am looking for a used amp with at least 400w per.

I just saw a beautiful Classe CA 300 on the GON and wonder if it's too old compared to a A21...

I'm out of my sandbox with this decision and not made of money... I am hoping this will be my last amp.

Mac pre > amp? > 10T's

Thanks... I need help lol