What are some of Weaknesses of MMA fighters?

What are some counters to when they grab you an attempt to take you down?

Also many say there is no-counter once they gain the submission lock? Is this true. is there away to escape submission lock. Is there a counter or a way one can squirm out of that painful posistion before having to tap out or getting a limb broken?

What sorta of fighters do MMA guys dread?