Why use Pentax?

I am a Nikon user but I am far from a fanboy.  My question is, why do people choose Pentax over big hitters like Nikon and Canon? I don't think I have ever seen anyone using a Pentax DSLR in person or in a photo. I have combed through dozens of photos of photographers but they all apper to be using Nikon and Canon products. I also looked into wedding and studio photographers. The ones that do mention what equipment they use, it is never Pentax.  Is that initself the allure; that few use it and it feels more special?

Thanks!