I'd go with Firespray if your looking for something your friends are going to be using in casual games. It's dial is the same as an x-wing (except for the K-turn I think), it has the same attack & agility as an x-wing, and twice the hull & shields. It's like a siamese twin X-wing on steroids. The advantage here is that the X-wing is a good, straight forward ship to learn with, and the Firespray add it's own flavor with crew, bombs, cannons and ordnance.

The Lambda is really good too, but it has a much steeper learning curve to take advantage of it's strengths rather than be hampered by it's dial. I just don't see it as a good choice for a casual or new player.