I have a few years experience with "R" bends and closed or twisted wire forms. I have used them both and I have caught fish on both. From my understanding the "R" bends are designed for direct tie. Where the closed form is better suited for using a snap swivel or leader. I really think it comes down to preference and application. There are a couple different pros and cons to both forms. The "R" bend with a direct tied knot will most likely run truer a majority of the time where a leader used on a twisted form may give the spinnerbait a little too much freedom and alloy it to tilt to the side. I also find that the "R" bends will bend more or "straighten" out more on a hook set. The "closed" wire forms I find don't open up as much and the wire seems to be slightly thicker in diameter. I guess this why they make most larger pike and musky spinnerbaits with all closed forms(to my knowledge anyways) Vibration may differ slightly from these two forms, but I honestly think the blades are responsible for most of the noise and vibration a spinnerbait puts out. I believe that the motion of the blades displacing water is what fish sense on their lateral line. Now if you believe that the "R" bend puts out more vibration that's great, use it in application where fish rely on there sense on lateral line primarily to feed such as stained water. If you like using the closed wire form you may want to use it more in situations where fish might rely on there sense of vision primarily to feed, such as clear water. I really think blades are what makes a spinnerbait. If it's vibration you want, colorado baldes are the way to go. If it's flash your going for, then twin willow blades are great.
Or you can do what I do, simply do what works and listen to the fish.