We get that question quite a bit. The short answer is none yet. We've had several near misses but no direct hits yet.
However, many of the pictures you see of shelters that are in tornado debris have likely not experienced F5 forces, otherwise they're be nothing standing but the shelter and the slab. Standing walls and lots of debris indicates the forces and velocities experienced by the pictured shelter were less than F5, even though the tornado itself may have been classified as such.
It depends on exactly where the shelter was in relation to the most violent part of the funnel. Most images I've seen have standing walls and lots of debris around the safe room, indicating it was closer to the edge of the path of destruction, not the center where the most violent winds are. You can see the exact same effect with hurricanes, whether you're located to the left, right or center of the eye when it makes landfall. For that reason, although it's a valid question there is a lot more than goes into the equation rather than just a straight thumbs up or thumbs down.
What you get with our safe rooms is verification that we do, in fact, meet or exceed all design and performance criteria published by FEMA, ICC-500 and the NSSA. Tornado Alley Armor is a Producer Member in the National Storm Shelter Association (NSSA), meaning that all our safe rooms have been not only impact tested successfully, but also that our entire design package has passed a mandated 3rd party engineering peer review to ensure we're not cutting corners. That's why there are so relatively few members in the NSSA vs. the other organization....because the required independent peer review knocks many of them out of contention to be members in the NSSA.
www.tornadoalleyarmor.com or toll free 855-552-7667