I’m lost. Help me find my way

I’m adding a headphone setup to my all McIntosh system. It’s shown in the virtual systems section. In short, it’s a HT system and the processor/preamp doesn’t have a headphone jack. 
My local dealer, who I have worked with since 1977, is recommending the McIntosh MHA200 amp and the Grado RS1x HP’s. I’m a Mac guy all the way since my first real system back in 70’s. I know nothing about Grado although everything I’ve seen gives them high marks. I respect and trust my dealer and will probably go with it unless I find the Grado phones uncomfortable or poor sounding after trying them. 
But I would welcome any first hand knowledge of either of these products. Thanks in advance.