I have the Bernina 550 and also the Bernina 830 LE, both have the stitch regulator, which I love. You can turn off the beeping sound if you don't like the noise, and then you can move the switch to regulate your speed, or you can just leave them on. It really does keep your stitches regulated and looks very nice for quilting or top stitching purposes.
Perhaps check with your Bernina dealer, and ask for a demonstration of the stitch regulator on one of their machines.
They will probably even let you try it out. No better way to find out for yourself, than to see exactly how it works.
I think you will be impressed, and you deserve to have a good working machine. Best of luck in your search.