Depends -- if you have a place that you can keep the bigger machines always setup, then by all means keep them all - but those suckers get heavier as we get older and moving them around can be a pain. If you are going to have to always be putting the machines away, then maybe the 3160 (which is only 12 pounds) would be the one to keep.
If you can keep one setup, I would pick the Babylock , but tuck the 3160 in a corner somewhere in case the Babylock has to go in for servicing.