A lot of people have some mis-perceptions of BJJ because of the old days when Royce Gracie was fighting in the UFC.
Although that shows what BJJ can do against opponents that are much larger and less skilled... MMA has evolved quite a large amount since then.
I often hear the retarded argument that "BJJ doesn't work against multiple opponents."
To the people that say that, I respond:
What if you come across 5 dudes just like Hector Lombard. All have awesome striking, takedowns, and BJJ. Although 5 of them would end your life, they just decide to send one guy in.
Video for reference: