Depends on if you're going to solo or group mostly. RC is the easiest solo spec with a common final of 47 RC, 26 Suppression, 5 Dark. For RVR it gives some utility with blue nearsight and 10 second PBT. Also have yellow cold debuff. You could up RC to 48 for the last cold debuff and go Darkcarver but not much utility.
47 Dark 26 Suppression is a better group spec. Keeps 10 sec PBT and blue nearsight, gains melee damage add, and debuffs its own damage type. Good nuking with some utility.
50 Suppression is your group support spec. 6 second PBT will get you groups easily and you get the best nearsight, which will be your primary RVR responsibility as it also interrupts. Put 19 in RC for the first GTAOE and better variance on your base bolt.
There are other specs but the above are the most common and imo most effective.
It depends on your group setup and what you are trying to do really.
PvE: 47 RC, 26 Supp - RC deals more AoE damage in bomb/caster setups. 47 Dark, 26 Supp - Damage add for your tanks and better single target dmg
RvR (8man/smallman): 47 dark 26 supp - if you are the only caster. 48 RC, 11 supp, 22 dark - if there are other casters in your group. You will be expected to be able to debuff.
How wrong they are... As solo the snare and damage rarely kill even a yellow con mob before it gets to you Duo trio...sure set up in a triangle and the mob is slowed periodically ....but it’s a huge mana drain and the mob would be dead far quicker with either of the other two lines
Just don’t bother with it The damage lines are useless in Supp line I see no reason for specking in the line unless it’s secondary ....and that really only for rvr if solo