Well, it's been more than a month since i finish the construction of the keyboard case. Since then it was always on the phone. It's now time to say what i think of it.
The battery of the keyboard does last long especially if i turn it off when i'm not using it. What i was pleased to discover, was that if i turn on the keyboard, it connects to the phone almost instantly.
Typing on this keyboard requie some getting used to, becase of the large size of it (typing with two thumbs), but after a few days, i typed really fast (alot better than the on screen keyboard).
The mousepad is very useful on the web browsing, where you access a website with drop-down menus. It is similar to a laptop mousepad. It is also usefull in the android interface, if you don't want to touch the screen. I think a mousepad would be a nice addition on the phones with large screens, if you simply don't want to move your hand over the entire screen (you can control the entire interface using only your right thumb).
Another usage of the keyboard is in games. I recently found Xash3d which is a port of half-life for android. I used to play half-life way back, on my pentium 3 pc, and i was pleased to play it again on the phone this time. The game has on-screen buttons, but without the hardware keyboard, i found it unplayable. Lukily, i was able to hide the on-screen buttons and play with the keyboard.
So in conclusion, i like this keyboard, it will always be on the phone.
So what's next? - The part 4 - Continuous improvement! - I have new ideas for the slide mechanism, and also ideas to make it thinner. Also in this part i will post a 3d model of the case that can be printed on a 3d printer.