Good if you always run a body. Bad if you don't. This is noted on their website and more than likely in the directions. I bought my savage one used. It held up well and saved me a few times.
I landed really bad on the rear and it buckled the two long parts of the cage from about 6 feet in the air at about 3/4 throttle... The cage contacted the dirt. They bent back, but I bent them again and when attempting to bend them back again, the busted off.
Without it, it would have more than likely cost me an engine, engine mount, engine mount plate, spur and possibly shocks. It absorbed all the impact and all parts of the truck were fine.