Oops, in my case I meant I've done both styles of debate.
Formal debates you have to be a little more clean cut, almost like you're testifying in court. I think there's a little too much emphasis on presentation here and that's why I don't always like it. Ignoring that, it's fun because you're not -really- supposed to insult character, but like most, I do it anyways very carefully. Basically I try to make them look incompetent and even if they have an overall better position, each of their words begins to have less influence.
This reminds me of a psych study awhile back. Basically there were 3 candidates going for mayor. 2 of them were always debating publicly (slandering one another while trying to promote themselves), while the other did absolutely nothing publicly, but had far more signs all over the city. "Vote _______ __________" that's all it said. Never said his stance on anything, all that jazz. Well, low and behold, he ended up winning. That's -generally- what I meant when I said too much emphasis on presentation and why I don't particularly like formal debates.
Informal you can skip the pleasantries and virtually go all out. Most people beat themselves in these ones.
Also, I'm curious how you bypass the Socratic method. They're pretty inquisitive questions and if you fail you respond you will likely hurt your own campaign. If you do respond, then you did what the other person wanted anyways. Unless you have a landslide lead on a topic, you almost always have to hit fire with fire in these cases.