My favourite modes are CS and HvH by far.
GA is a mode I don't really like because the games are over too fast and the only people that seem to get to play as hero etc. for most of the time are those that gather much BP in the first few minutes of the game.
Before CS was introduced, GA made me even turn away from this game as this mode made me feel that this game's spirit was to only give a lot of privileges to those that use some sometimes really cheesy (officer, star fighters) tactics to get as many BP as possible early on.
In CS on the other hand it's perfectly fine if you're not on top of the team's leaderboard right now. You can go ahead and have fun as tank or other reinforcement class without needing to worry that the match will be over in the next 5 minutes before you got to play as hero. Also you get BP from just capturing the ground objectives, which is easier to do while there are also more objectives than in a GA map. So in this mode you don't have to adapt to a play style you don't want to just because you want to have the chance to play as hero.
Also CS represents more a conquest mode while GA is a rush mode like we know from the Battlefield series.
That being said, I generally dislike rush modes as well, as these are too camper-heavy, one-sided, and with much less freedoms of movement and tactis than conquest modes.
When on board of the enemy dreadnought, the CS mode even reminds me of the titan mode from BF2142, which was a great mode as well.
Also the new Co-op mode is really nice to grind and unlock stuff from classes you normally don't want to play (or not with that specific weapon).