Join Date: Aug 2012
Location: Minneapolis, Minnesota
Nerites are fantastic for algae and dead plant matter, but they're the priciest option. They will not reproduce in a freshwater tank though, so if you buy 1 snail you'll always have only the 1 snail.
Apple snails tend to "burn out" quickly in an aquarium setting because they can't hibernate in the mud, so I usually don't recommend them.
Ramshorn snails and MTS are both my favorite options, but they can reproduce on their own even if you only start with one snail. So if you don't want to end up with a huge colony of them, don't go this route. MTS don't come out during the day though (they bury themselves in the substrate), so a tank full of them doesn't look infested or anything.
Hopefully that helps :)