Are you still not jailbreak & install Cydia for your iOS 8-8.1 device yet..?? This is your opportunity for that. Cydia has stabled on iOS 8 now. Cydia developer, Saurik says, the jailbreak platform is stable enough: Pangu 1.2.1 update with Cydia installer version 1.1.16, to download & install on iOS 8-8.1Also Saurik open the Cydia Store to the public. Now you can buy jailbreak apps & tweaks for your device from Cydia on iOS 8. Saurik has invited to Cydia vendors to mark their products as iOS 8 compatible.
An other side, Pangu has released Mac version for iOS 8.1 jailbreak & with that update, you are able to jailbreak iOS 8 with Pangu8 for both Window & Mac platform.
Meanwhile, Apple has released iOS 8.1.1 beta for developers and final version will be released within the next few days. We assume, it will fix the exploits used by the Pangu and cause jailbreak fail on iOS 8.1. Thus, we strongly advise you to update (Restore using iTunes) to iOS 8.1 and, then you are able jailbreak now or in the feature. Because, Apple will stop signing iOS 8.1, after released iOS 8.1.1