I've given my Beyond if let talk based on my How I Handle Optionals blog post about handling optionals in Swift twice this week. I was probably a more dynamic speaker in the NSLondon talk but the content is pretty similar. I may have been a bit slower and more methodical at the Swift London one though. Let me know if anything isn't clear in either of them or if you have any tips or suggestions (speaking or Swift).
Vimeo of talk at NSLondon. Questions from 13:30. [Updated to replace Livestream feed with this.]