Both versions have auto movement. For better accuracy (to gen) you'd want the version with the 7750 movement. The version you want is this one:
http://www.trustytime.com/index.php?main_page=product_info&cPath=261_371&products_id=1401
You don't have to buy it from Trusty. All dealers have this exact watch, but this is the version you want.
What you have to understand is that there are dealers, and there are factories. You only have access to dealers, not factories. My guess is that there is just factory making the higher grade Chopard, so they're all the same. All dealers buy this particular watch from the same factory. The less expensive 21J version is probably made by another factory, and again if you choose to get this one, all dealers would have access to the same watch. I hope it's clear.
BTW, I wouldn't necessary say the 21J movement is a "lesser" movement. It's less expensive, but most of these movements are rock solid reliable. I don't know why, but they've decided to put the 7750 in the better version (more accurate to gen) of this watch, therefore driving the price higher than necessary. May have to do with the second hand sweep, etc.