So I got the book. Here are my initial thoughts (from my completely Newbish perspective):
Gors don't look so great anymore. I feel like Bestigors are obvious must-haves and Ugors have a lot of uses but I can't quite see what I'd do with Gors. A tarpit, maybe?
I don't think Gors are too bad, taking a group of 30 of them is literally 10 or 20 points more expensive than taking a unit of 40 Ungors. They hit on 4+, which is better than the 5+ of the Ungors, and taking shields give them a +1 to their save in melee, though Ungors can do that too. If you take the Khorne Battalion, you don't have to take dual weapons and can rely on the shield, since Khorne gives the bonus of dual weapons to all units anyway. Plus they get an extra attack if you can keep them above 20 models, and since they have the Brayherd, keyword, teleport them somewhere where they can close with the enemy quickly, and you can have a pretty great initial swing with them.
They can tarpit pretty well I think with shields equipped, but don't forget the herdstone with that -1 to saves and the ignore battleshock, which will help them out a lot. No doubt you'll take Great Bray Shamans as well, give them tendrils of atrophy and stack that -1 save on a unit for -2.
Just some thoughts about them, they're only about 10 or 20 points more than Ungors if you compare the full sized units and their discounts. That makes me consider Gors way more than Ungors.
As for Bestigors, I think I actually prefer the Tzaangors with their two wounds, additional attacks (or additional accuracy) depending on their model count, plus the myriad of weapons you can bring in each squad makes me choose them over Bestigors. Though Bestigors are still wonderful and generally cheaper for a maxed out squad. That additional wound on each model for Tzaangors makes them better value in my book though. That's 60 wounds for a full squad! Pluuus, add in a Tzaangor Shaman to your list, and you're giving them buffs to their hits and wounds if you keep them together!