Deathmatch, though I don't mind Domination or Crazy King at all (as long as people aren't avoiding fights as much as humanly possible in Domination).

Capture the Relic and Chaosball have some potential, but there's too much of an advantage for Stamina builds in those game modes. Magicka setups often take a massive hit to their survivability and mobility while carrying the relic or ball, while Stam builds are entirely unaffected. Everyone eventually gets hosed by the healing debuff and/or incoming Chaosball damage, but Magicka gets it even worse since shields also become incredibly weak, but dodge rolling remains the same.

There's also the possibility for premade teams to be particularly obnoxious in Capture the Relic games, by refusing to actually let the game end before it times out, but I haven't seen that sort of "farming" of solo players in a long time.

Deathmatch > Capture the Relic > Chaosball > Domination > Crazy King

Crazy King is by far the worst, I couldn't tell you how many times the match-timer expires before any team reaches the score limit.
Domination is better than Crazy King because the flags don't move, so your team can just camp and hold 2 of the 4 flags; whereas Crazy King flag-spawns are pure RNG chance -- so do you fight over a current active flag that may despawn soon, or do you run to the other side of the map for the chance that the next flag spawns there, or elsewhere.

Capture the Relic and Chaosball are tons of fun if you want a break from Deathmatch.

I wish there was an option to toggle-off/lock-out 1 gamemode and/or 1 map from the BG matchmaking queue.
75%+ of the time that I queue for a 'random BG,' it is Crazy King. That does not seem very random, to me. And, that 90%+ is a very large sample-size, definitely over 50 matches played, since I started noticing/testing this.

Deathmatch is fun, but can be very frustrating because that's where the premades are.

Capture the relic is all right. Not terrible, not great. Would be much better if it was just 2 teams instead of 3.

Domination is not PvP.

Chaos Ball can be very fun because people tend to just focus the ball carrier, giving you the opportunity to wreak havoc while going somewhat unnoticed.

Crazy King is my favorite, perfect mix of playing the objective while PvPing at the same time.

I may or may not have crazy king and domination mixed up. Whatever though, i'm not changing the post.

yup... you knew it was coming ;D

Unless I am doing Dailies only really do landgrabs

My favorite game mode actually does not exist yet.... its called
SOLO QUE (NO PRE MADES ALLOWED)

Deathmatch

all the others seem designed for people to not fight

I play only deathmatch.
But I hate so much when I am grouped with more than 1 NB. 90% of them play so selfish.