Banshee is about 15% better than the standard Syfy movie of the week. That may not sound like a lot but it is enough. As the old saying goes, "You don't have to be faster than the bear, just faster than your friends."
Banshee is pretty simple when you get down to it. Bunch of young people, old geezers, and cops inexplicably encounter a banshee here in America. The Banshee is a case of CGI, and is less a creature of magic and myth than a seriously odd monster. It can make itself look like anyone, even a little girl. It can scream loud enough to blow heads off. It has big big big BIG claws. it's only weakness is that it doesn't like loud noises.
The plot is by the number. The acting ranges from fair to not their. The CGI is par for course. Still, there are some very nice scenes. Seeing a little girl holding an "I" beam over a soon to be dead character's head is visually interesting and thrilling. There are enough scenes like that to make it of interest to the horror fan.