I have had an SGC0554 grapple on my LX for over 5 years; it is undamaged. I have moved countless loads of brush, small trees, bigger logs, torn down large shed roof and timbers, big rocks and a few telephone poles with the grapple. A little thought and skill go a long way in preventing damage to your grapple, loader and tractor.
However, I do not use it to uproot bushes (including large privet), because I have found my bucket with toothbar to be much more effective. Open tines on a grapple (would vary with the design) let too much slip through, but a bucket with a toothbar catches everything. The tubes that span the grapple tines also limit your ability to dig down/get under things. You can dig with a bucket.
There are many great grapples with different designs (pros and cons to each). You should not expect too much from any grapple on your machine or any smaller compact tractor in terms of ripping stuff out of the ground, but grapples are the best tool for carrying and loading many types of debris.