I had the same one, it works pretty well. I just found there is a lot of background noise sometimes, but when you find the hb it is clear enough.
Just be careful of a couple of things. First it is easy to pick up your own heartbeat, you can youtube some videos that will explain the difference between the sounds you will hear so you are sure it is baby you are hearing. Also you can pick something up around 9-10 weeks, but at that stage if the baby turns around you won't hear it, so don't get too scared, most of the time it doesn't mean anything if you don't hear it. It will get more consistent after about 13 weeks.