Personally, I'm not a big fan of the 3 ball totes as the main carrier of my equipment. I have one for tournaments but do not use it for league play.
The analogy that I think is apt here is a sports car vs. SUV. The 3 ball tote as others have said is easier to maneuver,smaller, and more nimble. However, I just like the smoothness and lux feeling of a good 3 ball roller. I'm really liking my KR Krush Triple Roller with its big wheels and ample storage space.