I've used it for uni on a Linux tablet/convertible and it worked really quite well and has some nice convenient features for note-taking.
The UI looks like it's from android 4.something though ^^'
What I really appreciate about it is that its storage format are plain SVG(Z) which are extremely compatible. All you need to view your scribbles is an SVG viewer (i.e. a web browser) which basically every computer with a GUI has. Their website is in fact mostly just the output of their own app.
What do you mean by handwriting features? I've played around with Write a bit and it has some cool features (I really like the ability to make a series of stokes a link) but I wouldn't call them handwriting features.