I have both as well, and will echo the comment above. The desktop is more user friendly in regards to building recipes, setting up you equipment profile etc. It's also has all the add ons for the new yeasts, hops, grain and adjuncts. As far as I know, you can't just upload these add ons to the mobile app. When you transfer a recipe via the cloud from the desktop to the mobile app it does go with it. Personally i wouldn't recommend the mobile as a stand alone service, but that's just my opinion. It does have the timers, is good for shopping for ingredients, weighing out grains in the basement, and keeping all of that in your pocket.
Draft beer, Not me!!! - Belching Penguin