During the beta, we were introduced to skills that modified a character's Toughness, Battle Recovery and Speed. These have the potential to completely change the way your class can play, like a Speedy Warlock or Tough Hunter. Which of these attribute modifiers did you end up using during the beta, and which ones can you see yourself using in the future? These skills seem to be the same across the two subclasses.

Titan Skills
Titan Codex I: Training focused on battle recovery and toughness.
Titan Codex II: Training focused on on speed and toughness.
Titan Codex III: Training focused on battle recovery and speed.
Titan Codex IV: Training focused on all attributes.
Titan Codex V: Training focused on maximum battle recovery.
Titan Codex VI: Training focused on raw speed.

Hunter Skills
Path Forgotten: Training focused on toughness and speed.
Path Forbidden: Training focused on battle recovery and speed.
Path Unknown: Training focused on battle recovery and toughness.
Way of the Drifter: Training focused on all attributes.
Way of the Fearless: Training focused on toughness at all costs.
Way of the Nomad: Training focused on maximum battle recovery.

Warlock Skills
Arcane Wisdom: Training focused on battle recovery and speed.
Arcane Spirit: Training focused on battle recovery and toughness.
Arcane Force: Training focused on toughness and speed.
Ancestral Order: Training focused on all attributes.
Chaos Order: Training focused on speed.
Divine Order: Training focused on toughness at all costs.

I ended up trying Titan Codex II and found that I missed all that Battle Recovery. I may end up using Titan Codex V in the full version on my Defender Titan.

Path Forbidden: Training focused on battle recovery and speed.

This was the one I used mostly in the Beta. Hard to say for sure what I will use in the final game, especially because I am very interested in trying Bladedancer.

I took resilience and speed, assuming that it would be better to win the initial confrontation and then retreat to recover. However I could see speed and recovery given how often you would encounter several other players in a short space of time. I don't see the advantage of all recovery, since you are slower and have a lower health pool to start, and the weapons can kill a player in short order so the odds of you out healing incoming damage are low.