Welcome to Android Central! Of those 3 phones, the one with the best specs and battery life seems to be the ZTE Valet--it's also the only one that comes with Jellybean (the Centura comes with Ice Cream Sandwich, the Optimus with Gingerbread--not sure if either are updateable). Be aware, though, that it still only has a single core CPU, 512 MB of RAM and 2.3 GB of available internal storage, which means relatively slow performance and not much room to store a lot of apps, so keep your expectations in line. Good luck!