That sounds like a real negative. Keeping a string at the exact correct length can require quite a few twists over it's life. With not being able to twist your strings, you reduce one tuning option and will have to move nocking points. You will also have to accept lower brace heights, and lower maximum draw weights.

Maybe this is why Winners Choice pre-stretch their strings under such high tension. It may be the only way to get their system to work long term. I asked someone at Brownell about the high tension pre-stretch used by Winners Choice, and they said it wasn't recommended. It can damage the string material. I think they said not to tension them with any more then 300 pounds tension, for the best results. However, 300 lbs will not take all stretch out of a string and it will continue to creep a bit.