I have been experimenting with 450+ and find I like it, also a gentleman by the name of Doug Besherse sent me a string. I'm not sure what material it is. The 450+ has very little stretch or creep and is quiet and has a long life with good arrow speed. The string Doug sent me shoots very well also, a nice soft shot and no creep I mean none. I need to do some more testing with a chronograph. With the string from Doug I need to go up in spine with my arrows, when I get some built I will do the testing and let you know what I find.