Socket bonus

I'm wondering if this still is the case in 4.0.1

Socket Bonuses — Do They Matter?

Once your hunter is hit-capped the delicate cardinal ruby giving us +20 agility is by far and away the best gem for MM and SV hunters. So good, in fact, that it’s usually worth ignoring your socket bonuses and just putting in the delicate cardinal ruby.

The key word here is “usually.” The only way to know for certain what’s best for you is to use a spreadsheet to calculate EAP values for your character and your gear, then see how the EAP compares with a lesser gem with the socket vs the best gem.

As a general guideline here is what I have found: the delicate cardinal ruby is almost always better, even when it means losing the socket bonus. The exception seems to be when you have a yellow socket with a +4 agility bonus — then you’re better off with a Deadly Ametrine for +10agil and +10crit.

And don’t forget to meet your meta requirements! That means you’ll need one Nightmare Tear somewhere to satisfy a blue slot (and might as well be a blue gem slot so you can get the socket bonus).

Just to add to this, the socket bonus that is worth taking is the one such as in the leggings of northern lights at +8 agility. The ring ones, pre-patch were a 0.6/0.7 dps increase in my spreadsheets so they are worth it just they're not an emergency priority if filled with agility currently.

If you are using a blue or purple gem for hit purposes (most hunters near BiS icc 25 gear, normal or hc, are) drop the Nightmare tear (10 agi, stam, str, int ), juggle your sockets about to grab additional bonuses and throw in another agility gem somewhere.

I've been gemming yellow sockets with agi/haste as I already have excess crit and eke'ing out that last bit of acceptable haste brings my steady shots down to a nice "rotatable" time. Fortunately most of my socket bonuses are agility so win win there.