I have both upper arms done and will likely get my future child's name underneath the left arm.
Left arm is a crucifix with a marble style to it. Funny story, I didn't ask for the marble shading. Homie just did it and told me afterwards. Fortunately, I liked it. I didn't go back there for my right arm.
Right arm has the signs of the bushido.
Here's a fun game. One of the signs is slightly messed up - who knows which one?
***EDIT*** Also, as to the pain question(s) - it depends on where you get it done. The arms don't hurt so long as you don't go back to the soft skin. If it's flesh that's right over a bone expect it to hurt more. Honestly, it's an addictive feeling. After you get one done you really want to go get another. It feels... warm.