Im not even part of Skullcrushers and they always make me feel welcomed on their runs. As for getting yelled at, Ive never seen it in the group I run with. Loot wise, well lets just say the first night I ran with them I walked away with two new purples in my inventory.
Battlegrounds, only advice I have for you there is get a "thick skin". Unless you're part of a premade, there is ALWAYS someone yelling about something, be it people's gear or how they play, etc. etc. etc. I use the ignore button alot myself.