I'm buying a pentax k-7?

I found a Pentax k-7 for $700, it includes two pentax mount sigma lenses - 18-125mm and 70-300mm with macro. Is this camera worth buying over a Nikon d3100 which would cost me roughly $900 with lenses?

Pentax - everytime even without the saving. There's just so much more fun you can have with the massive variety of very cheap lenses that quickly adapt to the Pentax but not the Nikon. Weather proofing is important and worth $100s - one only has to read these pages with the "my camera got rained on and now doesn't work" plaints posted daily. That facility alone makes the K-7 worth double the Nikon's cost.