I have heard debate between metal knocking loops and string loops amongst my friends and i wanted to hear your opinion on the matter. im in the middle of the road on it because i believe they both have their positives and negatives.

Metal
+ Holds tight and doesnt allow the string to move within it, letting your peep open the same everytime
- will cut down on arrow velocity beacause of its weight



String
+ Lighter, arrow speed will not be effected too much
- will wear out or the bowstring will slip in it.