Two of my doors broke. You get a few battery changes and then the clasp breaks... The return process is ok... They did repair mine, gave me a new strap and sent it back in reasonable time.
However I also sent in a Aurora (another PT model) for repair of basically the same issue (battery clasp broke) and princeton tech replaced my translucent blue colored casing with an ugly olive drab opaque one. I am upset about that change, they could have at least informed me, if that was all they could do. It might only be color, but sending in a product and receiving a significantly different item back without notification is not appealing to myself. When I went through Petzl's service department, they actually took the time to call me with less-than-stellar news about my Duo.
This headlamp is ok; I do find use for it. But it certainly isn't a Petzl in quality or design... or warranty service. For myself, I think the quality of this headlamp/company is best summed up as, when it breaks again I will not bother to repair it or buying a similar one.