The cape colors. I love the ESB cape, it reminds me to a poncho or something from the far west. The greenish cape doesn't make too much sense IMO. And besides, you can conver half body with the ESB cape, but not with the ROTJ cape.
I also think that the ESB version has more military colors... I don't think that a feared bounty hunter likes to wear a yellow and blue jetpack. The green one is much sober.