Many people have warned that playing online games takes lots of time and causes sleep deprivation. I didn't realise that they meant that this happens just installing the thing.
I started installing it around 8PM. Once I had installed, updated and registered the online system, the game and both expansion packs, and created a character, I finally actually got to play the game just after midnight.
Thus as I needed sleep, I've only played it for about 20 minutes. Looks quite cool though.