I'm building a community app with videos for iOS and Android (maybe web too), so thinking about using Cordova to saving some time for MVP. I've done native on both before but never Cordova. So how much time % would it save roughly?
Where you've developed for both Native Android and Apple, Kinvey would likely save you time in implementing different functions, and time with setting up backends to handle resources generated from your applications.
As for Cordova, we aren't directly affiliated with them and make no claims as to how much time it could potentially save you. Where you have developed applications without Cordova in the past, it bears mentioning that the added complexity of adding an additional library could potentially increase your development time. You would probably be better served this question on the PhoneGap forums: https://groups.google.com/forum/#!forum/phonegap
Please let me know if you have any other questions.