Most of those sects spent their time trying to define what God is, how to get to it, and/or prove to non-beleivers it exists. It's not something I found convincing, and I felt I wasted my time reading on them since I'd already heard better definitions and "proofs" of God from Desecarte, Aristotle, Plato, and Aquinas, and even they're reasoning is faulty, but, with the exception of Aquinas, the concept of God was a marginal detail in what those men had to say. So, it really didn't matter.
I guess if you really want a Religion without heavy emphasis on scripture, one of these sects would be ideal. Though even then I would recommend Buddhism first; really, I recommend Buddhism, period, though I'm not one of them. Perhaps even Jainism; though I say Jainism hesitantly because their pacifism is beyond ridiculous. However for the most part, I don't think there's anything interesting to learn about from Gnostics, the Sufis, or Kabbalah. At least not anything you couldn't have heard in more concise terms from Plato et al.