For anyone that is interested, the newest installment of Rainbow Six is due soon.
Registration for the closed alpha is now open: http://rainbow6.ubi.com/siege/en-GB/ From the link you will need to answer a short survey (<1min) about your gaming habits/experience and your rigs performance.
The alpha required specs are fairly high, so check them out here before you apply.
Rainbow Six games are pretty well known to be highly tactical, with small squads often requiring a full team communicating over mics to be truly successful, while also utilizing fairly realistic gun handling mechanics.
I'll be using the alpha as an experience to determine whether I buy the final product or not, so if it is anything like the old RB6:Vegas 2 it's gonna be an absolute beast of a game.