Hey, I've been interested in the twiddler for quite a while but I've been hesitant to buy one since I haven't seen much evidence of anyone being actually proficient in using them, most of the videos on youtube are just unboxings and first impressions.
How fast can you type with it? Can it be easily used for key-combinations using modifier keys and such?
I'd say it's OK.
It's not even remotely on par with typing speed on laptop-size keyboard, but I'd say it provides a reasonable trade-off. And it has enough keys to use desktop software without much pain one way or another.
Half of it has.
Chorded keyboards are great, head mounted displays are still meh, but a typical smartphone is a wonderful display to strap to yourself.
Shameless plug: https://github.com/andrey-utkin/wearable-computer/