I think Dragon's P-51s are easily the best of the bunch, but Corgi's got more schemes... (unfortunatley the P-51D is one of their worst molds IMHO.). I don't have 'stangs from the other two, figured I have enough of 'em already from Dragon
I did a corgi/dragon comparison on my site a while back, check it out if you like:
http://www.diecastace.com/comparison..._Corgi_HR.html