do you have perfectly straight walls and a hellishly talented tile person? then go for stacked. otherwise brick, with not too much of a contrast of grout.

how many of these do you really want....

stacked would be more modern/contemporary. Agree, that if you go that route, hire someone who has skill and pays attention to detail. Preferably they have done it before and can show you their work.

i think its easier to get away with stacked for a kitchen backsplash, as there just arent that many tiles in a stack. for a shower, they go on and on. if the corner isnt square you'll see larger and larger tiles (or smaller and smaller) to keep the stacks straight. with brick pattern, it hides a bit more.