George, Music123 is now a subsidiary of GC just like MF. GC bought it and its sister Woodwind & Brasswind out of bankruptcy early last year. Each is operated as a separate company but the merchandise and pricing on each website is identical. And the return policies are the same. Almost all the merchandise comes out of the same Kansas City warehouse. GC's online division is part of this too.
When I had to return something to Music123 last fall and they sent me a prepaid return shipping label (because it was their mistake), the return was addressed to MF.
My headphones are for hi-fi listening, they don't have an exaggerated low end like some studio phones do, but they have good, clear low end. If the amp circuit is good, they'll sound good.