GWX or NYGM :p But ptobably the best isto download both and make two installs, then try which one your prefer. GWX ships more eye-candy, that's for sure. Wether it is more "realistic" than NYGM or the opposite is probably a matter of taste. Since none of us has experienced the U-Boot reality, it's all about which game play you prefer and seems to you more approximate to what you know about real life U-Boots.
