I have ramshorns. They're great at scavenging and eating algae. They don't eat plants [unlike many myths suggest] and most fish/bettas leave them alone. I enjoy watching mine, since they get somewhat large, but not massively big like a mystery/apple snail. I can't really think of any cons. They don't mess with other snails and they're easy to breed and maintain [in general and population]. My ramshorns are in my 10g heavily planted tank, and they never have a problem maneuvering in and out of the plants to get algae and other bits of food.
Here are some pics of my tank and ramshorns.