Try one and see if you do get a bow capable of ff. 450 plus is about as much better than fastflight as fastflight is above dacron. I agree that at hunting ranges -especially 10 yards lol) it will make no difference, but I like to shoot all year and practice out to 60 yards. The speed and decrease in noise are noticed, but the real advantage is tougher material( longer life of string as well as better abraision or cutting resistance)in the hunting environment. You really will not have a fear of cutting the string with a broadhead unless you really lay into it and bruch will not fray the newer materials.
Also, the lack of stretch eliminates the need to retune as often - especially when compaired to dacron which will continue to stretch and stretch. This is not as great an issue if a bow is true centershot as it is for us longbow shooters.
I think that on a older( most likely slower) bow, the difference is not as noticed, but on newer, faster, lower brace height, reflex/deflex bows speed will be noticed. Also, on the lower brace height bows, you will not run the risk of hitting yourhand/wrist juncture with no stretch strings as can happen with dacron ( I do not mean the wrist where arm guard covers). I know that if I put a dacron string on either of my two reflex/deflex longbows (6 1/2" brace heights), I have had the string hit the spot where my thumb meets my wrist.
In any case, regardless of the string material, flem strings are both more traditional and just plain look nicer and are easy to make. You can get plans for a jig on the internet and you probably have spare wood in the garage to make it out of. The version of archers bible that I have walks you through making a string (all it really is is braiding) as does my copy of traditional archery. It will also save you a ton of money as bow string bulk material is cheap and you can make one of much higher quality than the cheap strings sold in many stores. For me, making equipment is always much more fun than buying it - there is nothing like taking an animal with a arrow that you made knocked to a string you twisted, and shot from a bow that you made. Makes me want to get into smithing now so that I can learn to make broadheads, but my wife would most likely slay me with my own bow if I started one more hobby hehe.
Good luck this season.