Heu Mihi inquired yesterday what I thought about the affiliation of Helfta (Cistercian or Benedictine). I confess I hadn't much thought about the affiliation of Helfta before that point, so I poked around a little.
As it turns out, Helfta is interestingly eclectic in its spiritual affiliations and influences. This Saxon community of nuns was founded c. 1229. According to an article I recently read in Meredith Parsons Lillich, ed., Cistercian Nuns and their World, there's a definitely-Cistercian community that served as their mother house. It's not clear to me that this was a particularly strong link, mind you. Helfta was apparently never officially incorporated into the Cistercian Order, which leads some scholars to call it simply Benedictine; yet they did adopt some Cistercian customs.
So, do they walk, talk, and act like Cistercians? Sort of. They appear to be influenced by Cistercian spirituality, as discussed in Caroline Walker Bynum, Jesus as Mother. Yet according to several authorities, their spiritual advisors in the late 13th century were Dominican and/or Franciscan, possibly out of shared interests in mysticism. They thus appear to have accepted spiritual advice from many different sources and traditions. Their institutional commitment to learning is distinctive; I suspect most women's communities following Cistercian customs did not emphasize the trivium and quadrivium to the extent that Helfta's nuns did. And the Helfta nuns develop some original and distinctive devotions, such as devotion to the Sacred Heart. Rosalynn Voaden, in an essay in Medieval women in their communities, argues that the Helfta visionaries worked closely together and influenced each other, and has an interesting discussion of the Sacred Heart.
So, to sum up, Helfta is idiosyncratic; certainly following the Benedictine rule and Cistercian observances, although not officially recognized as Cistercian. The lack of oversight from a Cistercian father abbot may in fact have been helpful to them, allowing them greater autonomy in selecting spiritual guides and forging their unique community culture.