Design nit #1. The keyboard.
Exhibit A: iOS keyboard
Exhibit B: Gingerbread Keyboard
Visually, the design of these two things are quite similar. The only thing I’d say is that the letters on the iphone keyboard are easier to see IMHO. Probably because they use wider captial letters.
When it comes to actual interaction though, there are lots of differences. Te most noticeable was the way in which word suggestions are presented. Android suggests words much more aggressively than iOS, which was nice at first. The big problem is that the words appear next to the keyboard, and not next to the text as they do on iOS. I found that this actually caused me to type by looking mostly at they keyboard, whereas when I get going on the iphone, I watch the cursor position. Maybe this feels natural over time, but it felt very cumbersome to continue to check the suggestions, then check back at the actual text, and go back and forth, sometimes every other word.
Another small design problem on the Android: the “shifted” number keys. If you hold down a key on the top row which has a number label, after a timeout, the zoomed display shows the number instead of the letter. The problem is, once you’ve switched into number mode for that press, there’s no way to get back to the letter. This interacts pretty badly when you need to type precisely, and you’re using the zoom display to confirm each key that you input. This was also true for keys that had accented alternatives on hover, such as the “u” key. The u with various accents appears, but in those options, there is no non-accented “u”, which means you have to release, backspace, and then attempt to hit the u key again, if you want a plain u.
Finally, I like the cursor positioning interaction on iOS much better. On Android, you tap in the general area that you wan the cursor to appear, then you get a little orange handle to position it precisely. On iOS, just tap, hold, and position. One less step, and feels natural.
I wanted to try some of alternative android keyboards, but I couldn’t find swype in the app store (seemed like you have to install some package manually), and I found SwiftKey, which was suppose to do better prediction, but the basic manual input of letters was worse than the default, making it a non-starter.