If you can manage to download it in a day, sure. You can get it retail for £14.49, though, so it might be the better option in this particular case given that the Steam servers are probably being strangled. CoolShop (which is where it's being sold for the aforementioned price) also deliver incredibly fast in my experience.
Even still, it'd certainly be an excellent purchase at £17.99. Brilliant game.
Does Mass Effect 2 have any DLCs on steam, or is there only 1 version of the game?
Basically asking will there be a game of the year announcement in a few weeks or months with lots more content?
Last of all, 'The Void'. Any good?
I heard good things about it via PCGamer and Rock Paper Shotgun. The only gripe most players had was the difficulty, but there's a fan made patch that lowers it to a 'normal' level. Seems like one of those hidden gems of a game that most people look over.
Just bought it myself and its going near the top of my gaming backlog, looking forward to giving it a go.