I personally prefer paper. The idea is nice but reaching a perfect product is hard. I won't buy this, some thoughts:

- the pen is too big and low quality. It makes click noises when writing.

- you can't use any pen you want and writers like their pen (ballpoint, etc.).

- the battery lasts a week or so (not that much). When you use a pen you don't want to have to think about it (like with watches).

- not fast enough, sometimes it doesn't start quickly enough so you loose some words.

- not worth the 200$. The price is higher than some very capable full tablets with a pen.

- you can't use any notebook, you have to use their tablet notebook and buy it every time for 30$ or so.

- 229€ vs. 200$ (unfair as usual...)

So there's still work to do but one day this technology will be ready :)