Crisp and clean, devoid of distracting sound effects. For your listening pleasure, here's Nintendo's official release of Mega Man's Super Smash Bros. 3DS/Wii U theme. Namco's Rio Hamamoto oversaw the arrangement. He is perhaps best known for his work on the Tekken franchise, among others.
Gotta say, listening to this non-stop brings back wonderful feelings of Mega Man's initial reveal. The first time that footage rolled... man, the hype was real. So good!