The 'magic values' for both crit and surge are roughly 30% and 75% respectively (Crit rating will vary with willpower and talents, but surge at 75% is roughly 300). Those are about when you will start to eat the brunt end of diminishing returns.
By the strict math of it, Power gives a more consistent damage return over the long term, though that is mostly a concern for PvE.
In PvP, burst damage rains supreme. You need to crit often, crit hard, and spam controls to keep your opponent from doing the same. I know some that gun for roughly 40% (45 with buff) at 75% multiplier.
The only 'ideal' answers you will get are with respect to PvE, where the environment is predictable and controlled. In PvP, you'll mostly have to throw money and comms into the grinder until you get a performance that you are comfortable with.