BTC Mouse and Trackpad is not yet compatible with iOS 7 even if you jailbreak your device. I have just today received an email from the developer promising to make it compatible with iOS 7 in February. You should buy your iPad now and restore it to iOS 7.04 via iTunes (do not do upgrade over the air). Then, you can either jailbreak it now or jailbreak it later. Apple will most likely fix the vulnerability that the evaisi0n jailbreak uses in the next iOS update. You may be too late to the party if you don't purchase your ipad now and restore it to iOS 7.04 via iTunes. When a new iOS version comes out, do not upgrade your iPad until you make sure it can be jailbroken on that iOS version.