I'd like to ask the devs, but I doubt they have time at the moment.

I know the consoles are gonna suffer if they use GECK, or maybe they can fix the bugs- but I dunno about Aurora.. Hopefully if they use it they're gonna upgrade it.

What?
You want to know which engine they use?

I think they're using the one from Fo3.

Well, that's the point. It's only speculation at this point.

So which would you prefer?

They're using Gamebryo. Besides, Aurora isn't built for sandbox games.

Come on, this is... a bit stupid, to say the least. It's pretty clear they're using Gamebryo. I've never seen a first-person game that uses Aurora. Why is there even need for this question?

WOAH, Try your best not to be such an Interwebz Tough Guy. I understand you have a God Complex and everything, but try not to be such an ass.

And since when have developers ever been limited in the realm of editing engines? With Unreal, we've seen dozens of FPS and Third Person games.

Fallout shouldn't be a FPS anyways, I've always played it in the horrible 3P view. Hopefully Obsidian works out the kinks with that.

And it's not obvious at all if you're not spending every waking second of your life speculating that you're the smartest dude on the internet.

People like you give the internet a bad name.

Becasue that's what it was made for.

Closed for flaming.

As for the initial question, Obsidian is using the Fallout 3 engine as their base, presumably with some tweaks and adjustments - although we don't know how much.