Relevant:
viewtopic.php?f=43&t=10309viewtopic.php?f=43&t=10279What's good: Trying to run about with the flag is a wild goose chase instead of fast-paced trenchrunning around corners for a quick and high damaging shot. Of course not "better" than the alternative but it's a change of pace (possession is, for all intents and purposes, dead). Some maps are very good, some are very bad (especially before learning the layouts which can be convoluted as hell), some are middling.
What's bad: Half the time when someone's running from you, they're GONE because your shots literally can't reach the end of the corridor before they turn the corner. Sticking in the opponent's base and grabbing the flag on return is a very strong strategy because it's so difficult to kill them if they're focusing on staying alive, especially if you've respawned with just the buster. Due to this matches will often come to a standoff where both teams have the others' flag (though this isn't a bad thing). Flag carriers tend to bounce from health pickup to health pickup. There are weapons that can kill carriers, though how easy they are to get depends on the map. Often getting your flag back requires ambushing the carrier, cutting them off, or ganging up on them. There are many intrusive pits that will get the flag stuck until it auto-returns or someone suicides after it.
Oh right, and Classes is hugely popular and Classes doesn't play well with CTF at all. Ergo, dead game mode.
Standards: Lots of ring boomerang and sr50ing faster than bullets