I spend at least 10x more time thinking about mobile than desktop solutions. Mobile is interesting because of what it is going to enable people to do. Thinking further out and being focused on users two new devices I will have to play with will be the iPhone 5S and the Galaxy Note 3.
Actually, I am going to stick with my iPhone 5 and ordered two 5s's for my family so the 5s will be close at hand, but I won't spend time with it every day. I am the only Android user in the family, so I will have the Galaxy Note 3, upgrading from the Note 1 I bought 1 1/2 years ago. I was an early Note 1 users for the stylus and big screen. Something many don't think are important like the iPhone 5/5s audience.
Here is a comparison of size and resolution.
I'll get the new phones in two weeks and will write more on comparing. But, forewarned my focus is mainly on the Galaxy Note 3 because the target audience I am focusing on prefers the Galaxy Note 3 vs. the iPhone 5s. We will address the iPhone market, but first is the Galaxy Note.
It is so much easier to develop really cool solutions when you don't develop across multiple platforms. Think about it most of the mobile apps out there are cross platform or if they are on one platform, they really don't have to be.
Here is one piece of data iPhone 5/5s = 727,040 pixels on the screen vs. Samsung Galaxy Note 3 = 2,073,600 pixels on the screen. Almost 3X more pixels. There is a close relationship between the # of pixels you can see and the amount of information you can communicate.