I like these snails. I currently have a bunch of ramshorns (like in your pic), mini ramshorns (Planorbis arnodii, I think), and MTS. I used to have pond and bladder snails, but I think they got outcompeted or something.
I've never noticed them to harm plants, but they do clean up the dead plant material, and munch on algae and biofilms quite a bit. Great at clearing up new-driftwood fungus.