There is a learning curved to ruler work, but now that I've done some, I don't really find it harder than free motion quilting.
I really like the Clarity ruler foot; it's available on Patsy Thompson's website, or direct from Accents in Design (
http://www.accentsindesign.com). I find the clear foot much easier to work with than the metal one from Westalee. I also like the handles on their rulers; my fingers tend to cramp from holding flat rulers in place, but the handles prevent that. I would recommend these for anyone starting out.