I used it for a few years and just recently went back to a normal fingertip grip.  I had minimal loss of revs at first and it seemed I got back to normal not long after going to it.

I also ended up developing a higher tilt on my release.  Wasn't too noticeable at first, but with out proper practice to keep your hand behind the ball, you can tend to get around it too fast. 

The above changes made my equipment at the time react differently so they needed to be updated slightly.  I ended up changing the surface mainly.

I went back once I felt my finger could handle the stress again.  Good thing because I am able to stay behind the ball better now and am scoring better now also.

I had become uncomfortable with my release with the Sarge Easter.  The fit was fine and all, just wasn't bowling well and I felt I was having more and more difficulty staying behind the ball. 

So I figured I would try bowling with my old stuff to see if 1. I didn't feel any pain and 2. if it helped what I felt was my problem.  I was able to bowl without pain in my ring finger though I feel like my hand gets tired much faster right now.  And I have also bowled better.

Nothing wrong with wanting to shorten the span on the ring finger for a more relaxed grip.  But after my Sarge Easter requirement, I don't think I would do it if I hadn't hurt my finger.

Down side now is I only have one bowling ball I can use.