I personally find that it's a lot more to it than all these discussions about tris and quads.  It's all about how you actually model the clothing. What angle the faces are and where they are. That has a huge effects on how they drape.  If you have seams, don't just draw them onto the UVmap, but actually have the seams as faces in the model and so forth. It makes a -huge- difference, and in my opinion, a bigger difference than quads vs tris...

I've personally found that it's not necessarily a given. I sometimes use tris, sometimes quads, sometimes a combination, depending on what's needed. What really matters is that it looks good in the cloth simulator...

Your clothing looks good!  I'd give it some extra work around the collar. Also, the sleeves that go over the hands could probably be smoothened a bit and have some more polys added to them so the cloth simulation gets less jagged.

And yes, I'm a huge fan of dynamic clothing myself. :)