What program did you use?
It's by far the easiest to design flags in vector graphics editors, like inkscape. As a bonus, Wikipedia has most of its flags done in that same program, so you can just start working from those flags. A lot of coats of arms are converted to .svg as well.
Unfortunately 8chan still doesn't allow .svg uploads because it's possible to put some nasty html in them. I guess if you didn't allow them to show inline it would be fine, but oh well. Perhaps in infinity-next.
Visual appeal wise, I like the 3rd one the most for some reason. Perhaps just because the green Cross of Burgundy looks unique and it also works well with black and gold from the coat of arms. Granted, it's just a mashup of existing designs (pretty reasonable if you want to keep the symbolism) and not built from scratch, but it works well.