I love my Marantz. It has a great build quality and a hugely underrated amplifier. The tuners are highly selective, but have poor sensitivity. However, the main systems I've had since then dwarf it hugely by comparison. Call me a hi-fi snob, if you'd like. Although I'm comparing apples and oranges, 250W x 5 and a 400W sub, also all highly underrated, blow away even a 4400. Add a 4DD5, SQD-2020 and SH-3433 scope and ANY Marantz Quadradial can't even come close in all aspects of performance or versatility.
My modern surround preamp/amps with a 60" plasma and 27" iMac with wireless keyboard and mouse are far more Kirk-ish than my RC-4 and Marantz 4400 could ever hope to be. To have 13 digital discs loaded and several hundred hours of audio and video on hard drives, and switch between them wirelessly beats a remote with balance, volume and a loudness switch any day. 15 sources, plus the ability to stream hundreds of digital audio channels, hundreds of video channels, watch countless YouTube videos and download is something we couldn't have even dreamed of in the '70's. And not a single wire to trip over when you're drunk.
Sorry to rain on anyone's parade. Although a 4400 and RC-4 are still wonderful gear, a bigger scope, more power, better fidelity, more decoding/synthesizing options and no wires blast it to smithereens in every respect.
I've said it before and I'll say it again, ALL Quadraphones suck. The box on the 2+2 is a joke! I've owned several quadraphones and sold them all at retail when they were new. They make the Yugo seem like a great idea.