It's actually fun to scrutinize the DB manga to the DB/DBZ series, which is what I'm doing right now in my spare time. Yes, I am actually watching my DVDs while looking along in my manga. I'm a geek. That's why I'm here. In a lot of ways, they did a very close job of adapting the manga, even retaining most of the exact panels, and it's quite easy to follow along. But if they decide to change one thing, it can sometimes really throw everything off and make it completely different. I'm doing the Piccolo Daimou arc right now, and due to a few changes and filler the sequence of events is rearranged like crazy, and it's really hard to keep up.

The thing about filler is that, once you get to a certain point, you can tell that Toriyama is actually leaving things vague and unexplained on purpose so that Toei will have something to do. And that's usually where the best filler comes in, but it's also generally where the manga falls short. It's where Toei pulls their own stuff like extended flashbacks of scenes that occurred a month ago and trying to force extensions where they don't fit that the manga really shines, and the anime starts to lag.