Yes, there are many diffusion lines within the Michael Kors umbrella.
The mainline, called simply "Michael Kors," is a luxury line on par with any other designer line from Marc Jacobs to Dior to Gucci. Quality is fine, but the prices are often shocking.
KORS Michael Kors is, I believe, a women's diffusion line.
The line in question for men is MICHAEL Michael Kors. It is, as everybody has mentioned, rather crappy. The cuts are unflattering and dull, the fabrics are poor, and the shirts use cheap, plasticky buttons. While the mainline shirts are $300+, the MICHAEL line is perhaps $75, but even at this price point they are too expensive. They are no better than any shirt you'd get at JC Pennys for $19.99.
So, the suits as well are often touted at Nordstrom Rack or Off fifth as being $600 or so, marked down to $349, but I don't know that I'd pay more than $150 for one, and that was only if you REALLY liked the way it looked. Quality wise, you could get better for that price on the 'bay.
I think that initially this diffusion was intended to be a step above Van Heusen, Calvin Klein, and the like (other brands all owned by the same company), but it never really took off. I think that they aimed too low for the fashionista fans of Michael Kors (who 1) weren't going to shop at Dillards and 2) didn't want crappy, unflattering fits and fabrics) and they aimed too high for the regular, Van Heusen/Dillards/CK/Macy's market.
That's why we see so much of it on sale at Off Fifth, Nordstrom Rack, even at places like Marshall's, TJ Maxx, and Ross.