I don't think I would chuck my McGizmo lights onto concrete floors etc, but I can assure you that they are very resilient even the aluminium ones ie PD-s which I acquired 2nd hand from someone here in CPF some years back. It has its battle scars and since edc'ng that PD-s, I managed to put my own signatures on it with no ill effect. I did remember once it fell from my pocket onto hard tile and it stopped working. Very sad feeling indeed. In the end it was just the rechargeable battery which had somehow damaged due to the impact. Replaced it and it runs normally albeit some scuffing here and there.
Over time, the other two lights which are titanium will have their fair share of scuffs but its merely the anodized titanium layer that is scratched. A bit of spit and shine, it will take away the anodized layer and all is good. In a nutshell, these lights are very durable and For several years now, I have really enjoyed using them and hopefully I can still enjoy using them for many many more years to come.