I have the Sweet 16 and like it a lot. It is the same machine as the Baby Lock Tiara. One difference is that the table top level is (or at least used to be) different from the top level on the machine. This makes ruler work difficult unless you have the overlay. I ended up buying the overlay.
As for the stitch regulator, I have it but don't use it. It is easy enough to get yourself "regulated." I would not buy it again if I got a do-over.