Skirt VS Flank Steak?

I tried some grilled skirt steak at Catapalooza this year and it was delicious in tacos. My local butcher told me he doesn't carry skirt but has flank steak and claimed it was a better cut. It wasn't close. Bad cut or BS butcher?. What's the difference?. I'm working on my Albion contribution and want to get it right.
 

skirt is the diaphragm muscle which is located in front of the flank, the skirt is a smaller but well used muscle, hence the marbling and fat content, the flank is a larger muscle that is still used heavily but doesnt get the higher fat content, fat equals tenderness, both are great in there uses, but both need heavy marination and proper cutting,across the grain, the flank definately needs it more, it can take a good 8-12hrs of marination where the skirt can get by with 1-3, but since they are both heavily used muscles they will be chewy, but that chewiness is also flavor, look at a tenderloin, very soft and tender but bland, alot of butchers will keep the skirt for themselves, also the hanger or onglet in french, is known as the butchers steak, it also comes form the diaphragm and is my favorite cut, but there is only one per animal so its hard to find, hence the butcher steak, hope this helps, cameron

Both cuts are really good for nice and slow slow or fast/seared types of cooking.  Skirt steak usually has less connective tissues than Flank. They are both usually cheap, good for steak tacos, fajitas or london broil types of applications.

You also need to cut the steak properly, or you will just have chewy chewy bits of meat!

Skirt sliced thin and with just salt and pepper and grilled over a super hot charcoal quickly is my fav meat.Chopped into small pieces about 1/4inch square and you have some taco meat thats unbeatable. Skirt steak throwdown at Albion I say. Whaddya think?

also the hanger or onglet in french, is known as the butchers steak, it also comes form the diaphragm and is my favorite cut, but there is only one per animal so its hard to find, hence the butcher steak

Aka, Arrachera, in Mexico.  You can find it in most mexican grocery stores although its usually swimming in marinade (very tasty marinade).  I took about 2 lbs on a dive trip a couple months back and everyone dug it.

Wow. Cool, thanks.

skirt is the diaphragm muscle which is located in front of the flank, the skirt is a smaller but well used muscle, hence the marbling and fat content, the flank is a larger muscle that is still used heavily but doesnt get the higher fat content, fat equals tenderness, both are great in there uses, but both need heavy marination and proper cutting,across the grain, the flank definately needs it more, it can take a good 8-12hrs of marination where the skirt can get by with 1-3, but since they are both heavily used muscles they will be chewy, but that chewiness is also flavor, look at a tenderloin, very soft and tender but bland, alot of butchers will keep the skirt for themselves, also the hanger or onglet in french, is known as the butchers steak, it also comes form the diaphragm and is my favorite cut, but there is only one per animal so its hard to find, hence the butcher steak, hope this helps, cameron