Depends on the circumstances of the suffering. Is it highly likely that you're going to be horrifically tortured every day for the next 30 years? Then life is likely not worth it; chances are you're going to spend much of the rest of it being tortured or being haunted by the consequences (psychological or physical damage), and thus your life is likely to be negative and so the dice roll of death is a better choice.
However, the vast majority of people in the world's suffering is limited in scope compared to that. Sure, many live in poverty or danger, but they still have family and friends and hobbies, and aren't locked in a dark room having knives rammed into them every day - they still have some joys in their life. As such, generally it's pretty rare that the statistical unknown of death is a wiser choice than life.
Basically, death is only a better choice if there is a higher than 50% chance that a majority of your life is going to suck hardcore.
