No question shogun has an amazing chin, but u can't debate evan's chin, dude has never been ko (except mchida) but has been rocked many times. In my books he has a great chin unlike guys who have been rocked and it was lights out.
Pretty sure the only times we've seen Rashad get tagged clean is in the Machida fight and tonight against Silva. I'm not saying Rashad has no chin, Silva caught him flush with a big right hand and although wobbled, survived and covered well.
That said, Rampage is still going to take him out.