A pair of MC3500 mk IIs will set you back $60k.
Very different animals. At these price points, you really need to listen for yourself. I’ve heard both, and considered them to be worthy for audition by McIntosh aficionados. Obviously the 3500 is simpler. And the 901 requires speakers with dual inputs, so Wilsons would be off the table. But there are lots of other speaker options.