I actually have to agree with Gf2tw somewhat. As good as shielding is against Falcon, it's not going to shut him down. If a Bowser gets too shield happy, chances are the Falcon's going to start abusing his grab game to force Bowser into the air. Regardless of the fact that Falcon's ground game generally blows, it's extremely useful for shield pressuring and spacing, the two things that he actually needs in this match-up.
Sure, a Falcon NORMALLY sticks with his air game, but considering Bowser can shut that approach down for the most part, his next best option is the grab game. Which a good Falcon should be abusing anyway, regardless of the match-up, but eh. People use Falcon to look flashy and combo-video worthy, so they repeat the same stupid **** over and over hoping it'll hit.
A good Falcon won't do that, so I'm leaning more toward 55:45, than 50:50 or 60:40.
Also, I'm probably going to sap most of the information posted about this match-up and throw it into our board's guide, just so we won't have to go over it twice.