The pros are, I sincerely hope, that it gets me a reasonably polished first draft, not an awful mess.
The cons are that I write slowly. And that annoys the hell out of me.
Anyway, I said that I edit "a little" as I write, because I simply can't stop myself. But OTOH, I'm also being as firm as I can about not doing a full editing pass until I'm done with the first draft. I'm sincerely *trying* to "write first, edit later", I'm just fairly bad at it. 2/3