I understand that fast flight strings typically increase the velocity of the arrow and as a result are not as quiet. Trying to weigh out the pros and cons as I am in the market for some new strings. Thanks!
You'll typically get a very small increase in performance, comparing apples to apples...i.e., if you are comparing a 20 strand dacron string to a 10 strand 8125G on a 35# bow with arrows that weigh the same, that's not apples to apples and you'll see a big difference...but typically you're looking at maybe 2-5 fps., if even that.
As with most everything in this sport, there are variables. How the string is made can make a big difference in noise, performance, and durability--maybe as much or more than the material itself.
Comparing equally well made strings, one with dacron the other with an HMPE (FF) material, neither going to any extremes one way or the other, you can expect the "FF" to be stronger, more durable, have less elasticity(stretch) and elongation (creep). Strings that are very overbuilt or very underbuilt can negate some of the benefits.
String noise is usually a different pitch, but a little tinkering and tuning will go a long way. Tinker with the brace height first, to find the "sweet spot". Then add silencers and tie them on so they too can be tuned. Moving the silencers up or down the string as little as an inch can make a big difference in some bow's noise.
Once in a while folks come across a bow that seems to just "like" one material over another, but it's rare--usually it's just a matter of tuning or form/release. I personally have never owned a bow like that (I've owned quiet a few over the last 20 or so years), but I realize it can happen.
That being said, I much more prefer HMPE (FF) materials over dacron because of their durability and lack of stretch/creep. I only own a few bows that are not FF compatable, and I own them because they were gifts and hold a lot of sentimental value...they don't get shot nearly as much as my FF rated bows. I even put FF on my selfbows.
Dynaflight '97 and 8125G have been my long-time favorites, but the new 8190 is looking pretty good.
Chad