they are worth it. the only issues are as petrey said, you cant shoot groups. My twin has them and when you get close, they tend to break. when they break, you can cut out a whole section though, and it flies just as good. yah there is a speed loss, but we have noticed that they fly much better. the only rest you can really use is a drop away, which you need to fine tune so when the arrow leaves the string, the FOB doesnt make any contact with the rest, otherwise it flies haywire. any questions, please let me know