Hawkmoon is good, but not as great as you think it is. It is definitely not the best PS exclusive gun. That would be the 4th Horseman. With both of those guns getting a nerf soon, I'm not sure which will be better in the future, but as of now, 4th Horseman is much better than Hawkmoon (obviously not for pvp, but Hawkmoon isn't as consistently good as Thorn for PVP, so you're not missing out).