You'll ask that here? Well, all I can say is that I took one peek at the other one and decided....wow, I don't have that much time to keep up! This place is smallish, yet super friendly and helpful...I've only had a couple questions unanswered. I can keep up.
I use them both.... this is a pretty weird VS thread considering they are for different things, this is for android in general and droid forums is mainly for the moto droid.
As I said in another thread, I personally prefer this forum. I love the smallness of it and in my opinion, that forum is way too crowded. I don't like going through pages to find one thread. I like the smallness and simplicity of this forum.
If you're a Droid owner, Droidforums is it. However, that doesn't mean other forums aren't useful. For me, AC is better for the news articles. For everything else Droid, especially info on apps, rooting and roms, Droidforums is unbeatable. Phandroid is kinda in between.
This is the friendliest forum I've had the pleasure of being a part of. There is nothing worse than getting flamed for asking a question, and that just doesn't happen here.