8190 for me. I still like Dynaflight '97, never had any real problems with it, but 8190 is better.
To put it in perspective, Dyneema (the brand name for the HMPE that these materials are made from) comes in different grades.
Original "Fast Flight" (invented by the founders of BCY) was SK65 Dyneema. Dynaflight '97 and 8125 are SK75 Dyneema. Dynaflight 10 (still available as FORCE 10 x-bow string material) is SK78 Dyneema. 8190 Universal is SK90 Dyneema.
I never had a problem getting Dynaflight '97 quiet. Actually had lots of customers comment on how quiet it was on their bows. How the string is made and how it's tuned can make a huge difference.
I don't choose 8190, or any other material, because it's a couple of fps faster. I like it because it has less stretch and creep for stability, and it's more durable.
8190 is made from the highest grade Dyneema available, and is exclusive to BCY.
For serving I like Halo and 62XS. Very durable, comes in different sizes to fit different nocks.