It is my understanding that these are three different religious orders that each apply the Rule of St. Benedict in a different way, according to the traditions of their founder/reformer.
This website tells me:
That there is often not much difference in the way that the Rule is practised in communities today, but Cistercians and Trappists are stricter in their observances. So, they will often abstain from meat, be more self-sufficient - farming animals and so on, and never leave the monastery grounds.
I understand that the Cistercian and Trappist communities are reforms of the Benedictine's, and were created because of a perceived relaxation in Benedictine communities at the time.
Because there is often not much difference between the three as practised today, does this mean the "laxness" has been sorted out? If Benedictines tend to be less strict in their application, such as allowing monks to work outside the monastery or relying on means outside the community, is this a "bad" thing? Do Cistercians feel that the thier application is more in tune with what St. Benedict himself wanted, to the extent that they feel he would be displeased with the way the Benedictines follow his rule? For example, St. Benedict did say in his rule that communities were to be as self-sufficient as possible and were to abstain from meat - yet many Benedictine communities (correct my ignorance if I am wrong) do not do this.
Just trying to understand the way that these differences have come about.