I shot the string splitter for a few months this year. Like you, I thought it was a great idea, but after shooting it for a bit I decided it was not for me. I did not have any problems with arm slap, but I did notice a little extra noise from the string. My biggest problem with it was it was just too big which made a little harder for me to pick out a spot. I know it would be great in low light, but I went back to smaller peep and think I will stick with that since it has always worked before.