Well, this whole time I've thought G&W was a weakling. Til I tried him today. He's actually crazy good. He's powerful, and has this killer tactic, that lets you KO even heavy characters like Bower at 80%, and light characters like Meta Knight at 60%. Not to mention it's not extremely risky, and doesn't require charging like Ike's low % KOing moves. =P
Once you get someone to around 60-80% (depending on the character), which is easy to do with G&W due to his powerful moves, all G&W has to do is use his grab move, hit A like 2-3 times for 6%-9% more damage, then throw them down, and immediately use < or > smash. (depending on which direction they end up when you throw them down)
It's almost always a KO. >_< I'm tempted to main this beast now. Of course, in the last week, I've "mained" Lucario, Olimar, and Toon Link. I also was very close to making Diddy Kong and Pit my main. So yeah, we'll see how it goes.