Hey Indyfan, long time no speak, hope you are well.
A lot depends on your hair color. minoxidil tends to leave a white, dusty residue and if you have dark hair it can make you look like you are greying when it dries.
I also think that a sprayer is less economical, so much minoxidil used per spray that ends up on your hair instead of on your scalp.
I prefer the dropper.