Looks like your normal common / pond snail.
Love them or hate them they are fairly good for aqauriums as they help with algae and are a natural addition.
Personally I dont mind them at all and in fact have some Assassin snails as well as loads of MTS and ramshorn snails (in separate tanks).
Think snails are of more benefit to a tank than not, though of course if you overfeed your tank, then you will likely get overpopulation of snails. Though there are a few options on how to attempt to get rid of them.