I like the Silver Marantz models a lot but the silver C70s is not available in the US. The black Marantz models might as well be any other black AVR to me.
The X1800H looks ideal for my purposes - primarily 2.1 with occasional surround use and the $599 price on A4L makes it easy - I could sell my Wiim Amp Ultra to cover most of the cost...
I like both of them but I really wanted 2.2 so I sold my X1800H for that reason after happily using it for about 6 months. It’s SQ was as good as my other systems that cost much more. Based on available info, I am sure the C70 will sound the same if used under the same condition, but it also only has 2.1. If 2.1 is all you need, you will be happy with either, especially if you use the likes of the very affordable buckeye amp such as the NC252MP (I used it with the NC502MP).