I Love my rulers! I started doing ruler work on my Bernina before they made a Bernina ruler foot, so I have a Westalee foot on a #77 adapter. It works fine. The Bernina ruler foot is much nicer and has an adjustable height. The Westalee foot and adapter are almost the same price as the Bernina foot, but you get a Westalee ruler with theirs. If I could afford it, I'd get the Bernina foot.
Some of my best quilting has been straight lines with my walking foot. I don't know how I sewed without a walking foot! I Love it! The new Bernina walking foot has 3 soles and one is a stitch-in-the-ditch sole.