The best way to brew pu-erh actually depends on the pu-erh that you are brewing.
Raw pu-erh, or "sheng",can get bitter if over-brewed, and it is often brewed for only a few seconds at a time.
Cooked pu-erh, or "shu" really does not get bitter, no matter how long you let them steep. I have tried many different types of shu and have tried to make them get bitter....I have tried everything from excessively breaking the leaves, to leaving them in the water overnight, and none of the shu that I have tried (and I have tried many) have ever gotten bitter from over-brewing.
Also, different pu-erh teas come from different factories, so almost every "brand" has a different taste. I have found a few that were a little too "earthy" for my taste, but for the most part, I have enjoyed them. I prefer shu because of the fact that I can throw some in my filter cup, throw in some stevia leaves, and go.....without fear of bitterness.
If you would like more information on pu-erh tea, you can go to
www.pu-erh.net This site is a wealth of information for the person who has an interest in pu-erh tea.
Also, for plastic and glass cups that have a filter in the top so that the leaves don't get in your mouth, I shop at
http://www.xiuxiantea.com/?refkey=x3s4z7k9w8