I had one back in the 60's on a Schwinn. On one hand it was good...but on the other it was a PITA sometimes. Say you’re in low and have to stop, it puts you in high, so now you have to do the kickback again to get back in low. I was like 8, 9, 10 years old, so now at 57 I would probably like it. Another thing, the bike was almost too big for me, it was heavy, so with all of that it probably didn't help likening it. I'd say that if you can also add a front brake that would be a big plus! That way you wouldn't have to deal with the being in high if you don't have the time to kickback doing a stop. But like I said, I would probably like it now at my age.
Bob