In my opinion if you drink it too much it can be bad for health. When I drink too much, which i choose not to do, I can feel my heart rushing and getting cold sweat. Some internet sources claim that it can be addictive, but I never had any problem with it and I think it's bullshit. One cup and you're good to go. I highly recommend it over any coffee or energy drink. Even NaVi drank it at some point.
Here is my recipe:
Pour some water in a pot and warm it up.
Then when it gets close to boiling temperature add 1 or 2 teaspoons of pu-erh. (for 1 250ml cup 1 teaspoon is more than enough)
Boil it for several minutes, the more You boil, the stronger it gets. My friends even used to boil it for 20 minutes, but I usually do 3-5.
Then pour the the tea in a cup.
Add some milk and honey (best choice) or sugar.
It tastes really really good!