I use hoods on all my lenses. I prefer not to use filters due to IQ distortion, but a lens hood is great. Often hiking though the scrub forests and swamps for Florida, the hoods act as a shield from thorny branches and saw grass. I have never dropped my camera, but if I did I think a hood would do better to absorb the shock of the impact over any filter.
On the topic of 3rd party hoods, the shape of the hood is everything. If the hood is too long, it will show up in your image. If the hood is too shallow, it won't block the light. As long as the geometry of the 3rd party hood replicates the Canon version perfectly, I say go for it.
One example of a bad 3rd party choice is available for the 18-55 kit lens. Canon's version is an even cup. The 3rd party alternative is a petal hood. The 3rd party version may cost less and look better, but it just doesn't do its job...so you may have payed half price but you paid it in vain. Canon knows best what the hood should look like for best performance, just make sure the 3rd party company duplicates that.