I guessing that you'll be much happier with your apps written in Objective-C. They will be snappier, they will have instant access to new APIs as Apple releases them (as opposed to being tied to Adobe's flash engine update release cycle), they will probably consume less power and thus will make your users happier, and I'm not 100% sure the user experience is as good with flash apps in general. But, it's great to have a choice and it makes it plausible to "just get it out there" and then rewrite in objective-c if needed/required.
I wouldn't bet on Flash CS5 apps being accepted anytime soon. You're still required to adhere to the iOS look and feel, apps that behave differently will be rejected.