You may have seen in another thread that I'm planning to use my ATV in challenging terrain.
The picture is halfway up looking down at the mild part of the hill.  It has similar topography & trees on top but it gets steep in between.
So I bought a crush protection device, a QuadGuard from New Zealand.  There were shipping issues but I eventually got it with no extra charges.
It attaches to the rear rack and as a strength check I grabbed that rack the way people pick up fallen cruiser bikes, hands behind my back and lifting with my legs.  My doc said I can't lift heavy things any more so that's pushing the limit but it saved me a lot of time figuring out another way to test the rack.  I managed to lift both rear wheels off the ground without any change to the rack at all.
The rack is attached to the frame in 4 places and once to each rear fender.  It's not massive but like I said, nothing changed lifting the ATV by the outsides of the rack.  The QuadGuard retaining bars fit well in places that are "indeterminate" as far as force distribution goes but again, it passed the lifting test.
I did a few things to my brand-new QuadGuard that may have voided the warranty but I thought necessary for mosquito control and to avoid stinging insect occupation in advance.  I drilled 1/8" weep holes in the 4 bottom corners to let water out.  They are #1 and #2 in the picture.  The 2 big holes would let most water out but some could stay if the ATV were on an incline.  Mosquitoes only need a little water to breed.  At #3 and #4 I covered the holes and top opening with some plastic bug screen held by all-purpose pvc/abs adhesive.  I haven't tested how strong the bond is but it feels good.  I've tried taping the screen to things but it is made of plastic that just doesn't stick to tape.
The QuadQuard attaches with 2 bars, 4 bolts, and hook-shaped clamps that fit over the CForce 400's rack bars.  The square bars are almost the same dimension across corners as the round bars are in diameter.  The torgue specified is 7 Nt-M or 62 Inch-pounds, about 5 foot-pounds.  It is not a lot of torque but it squishes the bottom of the QuadQuard until the bolts reach the bars, then it reaches full torque quickly.
The ATV looks good front & rear.  My way getting on & off is unaffected.

Nice. How strong does it feel forwards/backwards, like if you go under a low tree branch and it hooks up, will it break do you think?

I'm confident it would handle smaller branches that would put maybe 20 pounds of force on it.
It isn't expected to be more than a single-use protection if I read everything right.
The manufacturer's videos show some distortion after a roll-over and they say it may be returned for inspection to see if it is still up to original usefulness.  That has to be considered in the light of having mandatory safety equipment in NZ.
I don't ever want to need it, like the air bags in a car.
I'm also thinking I'd like to see some evidence if somebody rolls my ATV when I'm not around.
That said, I estimate that a front-to-back force of 177 pounds will equal the stress of lifting both rear wheels by grabbing the back of the rack.
The QuadGuard is hollow molded similar to a $20 gas can except it is different plastic designed to be much thicker and stronger at the base while being thinner and flexible at the top. In the videos it wiggles from its own weight.  It has a welded seam just like my garden tool caddy I made from a gas can that started to leak, don't be shocked by how it is constructed.  I expect the cost of it will come down over time just like pocket calculators and cell phones did.  You'll need to make your own decision about what design meets your needs.  My purchase decision is based on a liability kind of thinking, like what will limit injuries if any, keeping a visible reminder that things can go wrong, and me having a counterpoint if my wife says I'm doing something too risky (old age etc considered).

I was looking at this and noticed some "typo" errors.
In the diagram, about the force on the Quadguard if you hit a branch of a small tree in one place, I made some mistakes.
The torque on the rack from lifting the ATV is half its weight times the distance to a mount and it is opposed by 2 x half the weight times the distance between mounts.  The distance is 14 inches so the torque shown is 5320 inch-pounds, not pounds.
At the top the torque should be inch pounds, not foot pounds. 
The dreaded purple pencil has been applied to the illustration above.
(Purple was once the color used to mark my tech drawings after the first corrections failed to make everything correct).