If you are looking for app that will record and allow you to save to your camera roll (export mp4s), then Explain Everything ($2.99) is still your best solution.
Created with Haiku Deck, the free presentation app for iPad
For more apps to share content/understanding you may want to take a look at my training for Top 10+ Creation Apps. And, as always, feel free to comment on your experience!
And, if you're an Edmodo user, feel free to join my group of curated resources for the classroom - complete with folders! Group code: nknmvo