Hmm, right now I'm leaning towards letting the DR680 go actually. I'm thinking that on very small projects I'll probably only use a boom and no wireless, and anything bigger will probably have budget to rent, or give me salary so I can invest on something more high-end.
Right now it looks like there wont be many offerings on the DR, so maybe the owner will lower the price. If so I might take it, but I don't think so.
Thanks for all your replies!