Best Merc spec from 50-70. (1-10) This is all.

Please just say for an example:

1. i/o: 7 - good range, low mobility, top two stats are X and Y. Depends on Accuracy to 110, the the rest crit

2. arsenal 9 - Nice aoe, strong dps and power management. Depends on Accuracy to 110, the the rest crit

This is just playing the story after hutt cartel to now. Thanks!

For playing story stuff, I'd always go arsenal. You have good aoe-damage and easy target-swapping, which you'll need to fight lots of low-health enemies that are common in the leveling process.

IO is kind of a pain to play, because enemies don't have enough health for your dots to really do anything before they are dead and playing IO without applying dots is basicaly playing a weaker version of arsenal.

Of course I'm not saying, that you can't make IO work, leveling is so easy that everything works. It's just gonna be a tad slower than arsenal.