About 1/100th of the content that New Vegas has. The map is deceptive at the start making you think theres so much left to do when in reality there is about 2 total worlds. The rest of the planets are pretty tiny maps. It is a good game but its incredibly short, especially when your expectations are not managed.
I was definitely surprised by the cue for the ending arc to begin. I have gotten a fair bit out of the sidequests though, so I've still got lots to do.