It puzzles me why Firefox can't support Antialias fonts and the same video types supported by Chrome and Safari. Will find a fix. Thanks for letting me know.
I'd say there is zero learning curve. So much easier to get started for anyone new. My favorite thing about Sketch is the ability to use Pages and Artboards + Symbols for multiple screens design. That's the way I prototype nowadays; focusing on interactions and flows rather than static single screens and branding/image editing.
Photoshop has been too hard to use for anyone outside the design community to want to learn. It's the new MS word. The export for 1x, 1.5x, 2x, etc. could be useful for making assets for Android.
Hmm, popcorn is a single chatroom within a location. Ripple is multiple chatrooms within a location, but based on a topic. There is no signup. That actually creates some really interesting use cases. Hopefully, you'll decide to try it out! :)
Thanks for mentioning Roboto, I agree that it's a much nicer font. It's also good to know that it isn't too hard to embed custom fonts. I was definitely looking for that answer.
Disclaimer: I'm the author of the book. I'm happy to answer any question.