Try ghost shrimp too - not too heavy on the load of the tank, and fun to watch. Depends what else you have in the tank.
Otos do a great job cleaning off plants, and certainly don't eat the plants.
Otos won't eat all kinds of algae, neither will shrimp... as for snails... unless you buy specific kinds (I think Apple snails might be one), they will multiply on their own... I stopped counting how many MTS I have in my tank.
first figure out what kind of algae you're dealing with... then find the appropriate algae eater to deal with it.
You might also want to check out your nutrients levels... might be an imbalance there that no amount of algae-eater will resolve (i've been through the algae-eater additions, reduced lighting, black-out, you name it - just to find that proper nutrients solved the problem).