From my understanding it's similar to Gnosticism, in that it pertains to a revelation of God rather than a faith based approach (seems mystical, but from what I've read, some adherents do not like it referred to as mysticism). It divides God into an impersonal 'unknowable' aspect, and a 'revealed' aspect that communicates with humanity. The Tetragrammaton is read in multiple combinations, with each one describing an aspect of the divine. It's an interesting system of interpretation.
I have a friend who reads a lot of Kabbalah texts, and he's also heavily into Gnosticism. He only studies it personally, so I couldn't comment on any cultish or religious aspects of it. Like any religious system, it probably has the potential to be cultish.
I'm not familiar with any scientific claims on the Kabbalah, but it seems that many throw the word science around way too much without knowing what it really means.