Hi, and welcome!
These two aren't really comparable, I don't think. The Marantz is a stereo receiver, so includes a radio tuner. The Yamaha is a stereo amplifier, and has been highly praised in its category (though the new Marantz PM6004 looks like a winner).
Can you help us by saying what you listen to (music types and media - CDs, LPs, anything else?) and what speakers, and room layout/size?