You really don't wanna use GravityBox... mainly because the dev don't really like anyone who's not using a Nexus. Sense Toolbox will change the functionality of the navbar buttons... GravityBox will too, but a bunch of things don't work. Ironically, on the Galaxy S3, more stuff in GravityBox works in TouchWiz than CM. Yep, even in CM, which is as close to AOSP as you can get without running a Nexus, stuff in GB is broken. Anyway, unless GB has something real special ST doesn't... I'd just stick with ST, provided you're running a Sense ROM, that is. If you're GPE, take your chances with GB. Might work, might not, not sure on that count.