I agree with Brute 23 - it's all about how it feels to the shooter. I won the SKB RS300 in a raffle before she started shooting, so it's what she learned with. It's built for clays, with a fully adjustable stock. We tweaked it a little for her, and away she went. This spring, exactly a week before the state shoot, the pin holding the trigger assembly in place broke. Her trap coach/sponsor (also her ag teacher and our good friend) called SKB for a new pin - they said that should never happen and asked us to send them the gun. We overnighted it to them on a Wednesday and on the following Monday they overnighted us a brand new gun - a couple of years newer model of the same gun. They picked it up on the way to the state shoot. Before all this she was consistently hitting around 20. For those 6 days she had practiced with everything we could get our hands and couldn't get anything to suit her (mostly the lower end pumps and o/u's that most of her teammates shoot) and was so happy to get her gun back - except it wasn't hers. All those adjustments we'd made were gone. For whatever reason, she hit about half her usual score, so we're just looking for something else she can get used to, just in case.
All that said, a couple of the better shooters among her teammates are shooting 870 Express models, and she seemed to get along as well with those as anything else, so that was part of why we were considering one. One has a Browning BPS, but my daughter never got a chance to shoot it. There are a couple of fairly nice o/u's in the group, but she's not sure about them. She hasn't been shooting skeet, but the state FFA skeet shoot requires o/u's, but they provide the guns for their shoot. That's why several of the other kids have gone to o/u for trap as well.
I hadn't done any research on the wingmaster before I posted this. What you all say reinforces what I have learned today. We'll look at the wingmaster tomorrow - I'm sure he'll have some other stuff to look at, too. Thanks everyone for your replies - I'll let you know what I come up with.