I strongly prefer cowls. Eye masks have too little coverage while Spider-Gwen full masks are too androgynous and alien-looking.
The Batgirl-style cowl used in MH's KnightWoman videos is my personal favorite.
This cowl is skintight, retaining the size and contours of the female head. It shows exactly the right amount of face (eyes, mouth, chin and nose-tip) to appreciate the wearer's beauty. It has good coverage of the neck, allowing the mask to blend into a matching costume/cape. The ponytail hole at the back allows the wearers feminine long hair to be visible. Finally, the pliable fabric can be teased gradually during an unmasking scene.
It's probably the best live action realization of how skintight batcowls looked in the Silver Age comics.
The alternative Yvonne Craig-style rigid masks are okay-ish. However, most of them fit the models quite poorly. Often, the front of the cowl won't be touching the wearer's face, sometimes suspended a full inch away from her skin. Jim Weathers is one of the few producers whose YC-style cowls actually fit the models well. But then, Jim's always meticulous over details. Matching that type of cowl with a good wig seems to help.
As for the Rubie's party store version with the weirdly mournful eye holes and the fucking Ronald McDonald curly red clown wig, that piece of shit is truly an abomination.