Some authors refer to it as costumary internacional law, other as general international law. My research is focused mostly in the 2001 Articles on the Responsibility of States for Internationally Wrongful Acts.
I would them somewhere between an ICJ opinion and a GA resolution passed by consensus, in that they probably represent the international custom (opinio juris), but since it is only the expression of legal experts rather than state representatives it cannot be considered binding.
They are an important source to identify whether some norms are candidates for being customary law. Yet they only represent an opinio iuris and necessitate corroborative evidence of being sufficiently accepted and followed before one could infer binding norms from them. The same argument could be made for using them to identify structural principles. For the latter though, they carry more weight.
As to the draft articles themselves, they are indeed soft law. Hence, they provide some guidance, but cannot be considered binding by themselves. The best way to classify them would be by analogy to draft bills at national level during their passage through variois committees. They are "known" to the whole state, yet they can never be more binding than the subsequent actual bill. An upper bound is therefore the binding character of a GA resolution and they.should always be placed at an inferior level.
On the flipside, due to their high level and reknown generative process, they cannot be treated the same way as bogus drafts blossoming in some national legislatures. From this follows their strong characterisation as soft law: norms that SHOULD be followed to the best of knowledge and whose consideration is to be EXPECTED but not with a binding character. To break this down more practically: Their violation has to be justified, but does not entail any grounds for retorsion or reprisal.
I recommend that you read the UN General Assembly Sixth Committee debates about the status of the articles. States (as well as scholars) take different views as to whether the content of any of the articles reflects customary international law. The status of particular articles has also been discussed in some national and international court judgments. http://www.un.org/en/ga/sixth/71/resp_of_states.shtml.
One day ago I wrote something about articles. In my opinion it will be very hard to discuss about legal status of the project of articles on responsibility of states for internationally wrongful acts designed by the International Law Commission in 2001.
If you haven't something against, let me put your attention for example on art. 25. It allows the possibility of exceptional cases in which the only means by which the state can preserve its vital interests threatened by the inevitable danger is failing to perform other international obligations or to lesser importance or urgency. Under the conditions strictly defined in Art. 25 it is possible to exclude the unlawfulness of the act.
One of the most characteristic contemporary example of acts which unlawfulness is excluded on this basis is Japan's conduct in the Okinotorishima case, which consist clear violation of the United Nations Convention on the Law of the Sea.
It's only example, but if we try to start discuss about it we can find much more evidences that states in fact don't want to recognize legal status of theses articles.
I think that the Articles have come a long way. They have evolved over time and states have grown accustomed to relying on it where necessary, so it is recognized as customary international law. However, as regards its bindingness, i would say that it is not binding in itself, but highly persuasive since states, judicial bodies, the courts and even academics rely on it heavily to buttress arguments and justify measures taken by states in seeking redress.