Firstly, it's FREE.
Secondly, it's a small download (~500mb) and is not demanding in terms of computer specs.
Thirdly: it's good fun!
Already a thread for Tribes:Ascend, but this is the earlier version (still regarded by many as being the 'true Tribes').
It's a very difficult game to get good at - there's alot of skills needed as it's mostly projectile based. This means you need to lead your target, and it's very hard to hit when starting. There's also 'skiing' (holding jump to attempt to slide and gain momentum) which again takes alot of time to get right.
I've been playing for a week and I'm still only getting a hundred points per match (only a few kills). I'd just like to see more new people playing the game so I don't constantly get mullered by Talent and his friends :D It's fun, if not very challenging.
Gameplay (clan-match) video/commentary: http://www.youtube.com/watch?v=igjM6KOm8ZE
IRC channel I'll start to setup: #aos.tribes2
Download the full version, then the multiplayer patch from here: http://www.tribesnext.com/downloads