We use Fighting Styles a lot, either modified versions of the Quint Fighter ones, or homebrew ones. We have a house rule that you can only take a level in a Fighting Style when levelling up, and it costs 1 skill point/level, we've done away with the ridiculous WIS requirement. In our campaigns we've used a modified version of the Orask (Blood-Bond) style for a PC bonded with his sentient blood-drinking artifact weapon (it fits perfectly!), "Lightning & Thunder", a homebrew Sword & Shield style very loosely based on the Style of Cordun, the unmodified Style of Cordun for a short-lived PC, and a modified Fegrin's Pair style that became "Feruin's Pair", an elven knife-fighting style.
Our campaigns are generally lowish-magic and Fighter-oriented, so the Styles help differentiate the non-spellcasting PCs and help keep parity w spellcaster PCs.