I'm for dynamic, capped ability scores with one giganic caveat: I'm against ability scores affecting basic combat capabilities. I believe that high-level fantasy superheroes should be able to move mountains, hear a cat breathing behind a locked door across the street, and read and memorize the forty-seven scriptures of Tiamat in four hours flat. However, I don't want this to cause extremely confusing, complicated and unbalanced math when it comes to combat.
If ability scores absolutely have to figure into combat mechanics, fixed scores are probably prefferable, if they're generated in a fair way.
If ability scores absolutely have to figure into combat mechanics, fixed scores are probably prefferable, if they're generated in a fair way.