Another benefit to image-sequence, which I've rarely seen mentioned, is that you can preview the results while the animation is still being rendered.

I'm currently in the midst of rendering a 90-second clip, but can load the finished frames into VDub to see how it's turning out.  If I found visible flaws at any point in the sequence, I could cancel the render process, make the necessary corrections to the scene, and then resume rendering from that point, instead of discovering them after the entire animation was done.