Slashers are horror man, slashers are easily my favorite sub-genre next to zombies.
I love the Prowler and I remember as a kid Maniac scared the hell out of me.
I kinda separate the 2. For me horror is a movie that scares me because is scary, slashers aren't necessary scary, just a blood bath that has music to scare you. Don't know if that made sense. Example, Exorcist to me is Horror, Friday the 13th, slasher. But I know they are always under one category.
I recently discovered Prowler and Maniac within the last 6-7 months. I feel The Prowler holds it own. Maniac was pretty sick, I can't believe I jumped in the part when he's on top of that model in the apartment towards the end. Just got caught up in the moment I guess. The Tom Savini scene in the car is probably the best kill I have ever scene. Loved it.