I'm just curious about what the general consensus is on this game.  I'm interested in it, as I have a problem with buying downloadable games like some kind of junk-sick drug addict.  It looks pretty fun to me.

Just play Quake Live, it's a better version of this game and it's free. I was about to buy the XBLA version to have the chance to play against people who aren't insanely good. However, $15 is asking a lot. XBLA games have a bad track record with multiplayer audiences.

As a console player, I've never played Quake, and as someone who doesn't like keyboard/mouse control, I never will, because I sure as hell am not going to pay for something that's free on the web. 

Quake live is free and you can play it in a browser. 
 
Why would you ever spend money on Quake Arena Live?

No, because there are plenty of other opportunities to play Quake elsewhere. Also X-Men Arcade.

loved Q3 back in the day, and Quake Live is sweet. Quake 3 was (and in many ways still is) the fastest and purest example of a Deathmatch FPS. The Xbox version, however, feels like a lazy port ... no concession has been made for playing with a controller - feels like how FPS games used to be on consoles before Halo - just a PC developed title ported over with little thought. Also, considering the stat tracking available with Quake Live, I'm surprised at its apparent absence in this game... there's no player profile page to view W/L, K/D ratios or how many medals you've earnt. 
 
At its core though, Quake Arcade is Quake 3 and Quake 3 is still fun as hell. The game moves at a smooth frame rate as well, so much so that when I returned to Halo Reach after a quick Quake bash I thought something was wrong with Reach - the frame rate seemed so jarringly clunky. But no, that's just modern day FPS games for you, all running at 30fps instead of 60 (that said, I got over it pretty quickly).
 
In many ways Halo is the natural evolution of the Quake 3 formula - more so than Modern Warfare or Battlefield. Its slower, certainly, but that actually benefits the game when played on a controller. If you love Halo and haven't played Quake before you might find Quake Arcade a tad simplistic or you could love it's pure, fast take on what is essentially the same formula. However, if you have the ability to play Quake Live on a PC, then I'd stick with that. If not, and you don't feel my above observations will adversely affect your enjoyment, you should certainly give it a go, even if just to play one of the most influential games of all time :)
 
That said, I'm not getting - I'll stick with Quake Live and Halo Reach.

 Its free elsewhere, so why would i pay?

Thanks for all the replies.  I'll probably take a pass on the game, but might check it out if it goes on super sale or something.