What are you defining as "doing loops" and "overdubbing"....?
Overdubbing can be just recording another channel - ie. just recording, or are you referring to punching in and out in real time and correcting errors?
Loops are just repeating things. You'll find it difficult to "do loops" on a machine with the GUI of an AW1600 - editing on these things is a bit of a bitch - to do loops you need a good GUI that you can map your tracks against in time exactly, with "snap to grid" type functionality, or as you layer things you're going to not get things to line up exactly. I wouldn't use one of these for stuff like that. I have an AW4416, sort of the daddy of the AW1600... it would be impossible on that, can't imagine it's any easier on your machine.
