I have both. The F14 can sound good as long as it isn't close to the beater. When I used it, I put it just inside the port of the resonant head. Now I use a beta52, so the f14 only gets used on floor toms if I run out of mics.
I've only used my f15 on hats, and I really haven't been able to get anything special out of it. It feels heavy and looks nice though.