There are two general methods of how one can approach ancient systems of thought like Epicureanism and Stoicism. The first is a top-down view, where one looks at the general principles of the school of thought. If one finds them wanting, one can also dismiss the individual ideas of that school as useless.
The other option is to look at the individual ideas and evaluate their worth at solving independent issues. At this point, it is good to remember that if you go through the works of Aristotle, you will find that he made countless elementary and even childish mistakes. However, he is still revered because his some other ideas are still seen as vital.
Similarly, I do not agree with Epicurus in some issues like participating in politics and on his attitude towards sex. However, I can still forward almost all of his other ideas that I see as still valuable and worthwhile after 2400 years. There is just a small step from here towards my attitude on the Stoic philosophy. There are many basic concepts that I do not agree with in Stoicism. For example, their pantheism is not for me at all.
This is true, even if pantheism is the most rational idea of a "god" that there does exist. The pantheistic idea of Nature and the universe as a god is a natural one. It is an idea that also Baruch Spinoza and Albert Einstein also held. The idea of Earth as one organism or Gaia is also extremely similar.
The Stoic idea of not letting your bare emotions make your life miserable is not about repressing emotions as many opponents of Stoic thinking say. It is about striving into being able to control ones own emotions to a certain degree. There is a common misconception in this respect.
Anyway, the idea that all ideologies and philosophies can contain valuable and important individual ideas is obviously strange and even dangerous one for all too many people. Most people seem to be happy to choose one pet ideology as their own and discard all the rest with one swell swoop. Most of all religious ideologies (but also ideologies like communism) are constructed in a way that makes it hard to accept ideas from other ideologies. The very idea of picking the best ideas from several ideologies is simply dangerous anathema to very many people on this little blue planet.
In the end, the only tool that one can rely on in picking and choosing of best ideas from different and even competing ideologies is ones own reason. This tool will, normally develop further during the process of acquainting oneself with different ideas and ideologies.
The process of learning a single ideology even deeply just cannot produce similar results as does the opening of ones mind to different possibilities and situations in human life as study of large array of different ideas can. One can even learn the ultimate goal of accepting that there just might be not just one right answer to human and social problems. There can be several good and acceptable answers at the same time.
Naturally to be able to conduct policies in the real one, one needs to choose the ideas that he or she wants to forward. However, one can at the same time accept the fact that even a competing idea can have some merit. In an ideal world, one will be able to choose the idea that best suits the current situation in hand. I know that this is simply impossible in the real world. People do become so easily attached to single ideologies, that the ability to evaluate freely different ideas and ideologies does exist only in theory.
One can well ask what can make a person choose, for example, Epicureanism in the first place? It is a bit circular reasoning to say that some of the Epicurean ideals makes him choose it. People choose it if they see this system of thought as reasonable and valid. This really happens as a rational process, because Epicureanism in never learned in childhood like religions. Choosing it is always a decision that is made by a reasonable adult.
They use reason to choose Epicureanism. This is not the Reason of Platonist's, but the reasoning of Karl Popper and Bertrand Russell. Most of all Russell has been instrumental in showing me how important questions in human social life can have several valid answers at the same time. He did show me how there can be no absolute and final truth in these matters.
Of course, there are many things in the natural world that have a quite stable answer, but even things like the size of the Sun or distance from Earth to Moon do change every second. However, I do speak now strictly only about human social behavior and interactions. Human societies and human interactions are so varied that there simply cannot be one answer.
One answer simply can bit cover all possible variations in complex modern human societies. Sadly many people like so many devout Christians or followers of Islam still do think so. However, it is good always to remember that one size simply does not fit all. The more complex a society is the more varied the ideas need to be that are used to guide that society.
This piece is loosely based on my comments on a discussion I had in the Epicurean discussion-group "The Garden of Epicurus" at http://www.facebook.com/groups/gardenofepicurus/
It is a closed group, but all newcomers have been accepted thus far. I founded it a few years ago, but it has been going strong even without me for a long time.