Look at what type of hardware and what gauge of steel each is built out of. I am not familiar with Martin brand doors, but I would bet they offer better hardware and heavier gauge steel.

It is worth the extra money to buy the heavier gauge steel with heavier gauge hardware. It lasts a lot longer.

Martin doors are known for their safety guards. A few weeks ago in Washington state a child died when the garage door opener malfunctioned and the door slammed down. That's one thing that won't happen with a Martin. They also have finger protections as well.