SDA is not as "closed" and rejecting of the doctrine of "faith-alone" and non-SDA's as necessarily "lost" as other groups (such as most of the other sabbatarians, and the JW's, etc.) and also accept the Trinity, which is the main thing that "gets them over" to CRI and some others. (That's the number one "deal-breaker" for accepting a movement or not).
Still, just because one leader and ministry (Martin/CRI, and the ministries he lists in the book as saying they're not a cult) declares a group not a cult doesn't mean the group's teachings are right. For that would be to essentially assign to that ministry and leaders the ultimate authority in truth. Like what they declare as true or not means so much, and proves your group is true. Those same authorities still say Sunday, eternal Hell and non-kosker diet are the true Christian beliefs, and you believe they're wrong on those points, so what does them saying SDA is not a cult because of them (i.e. you're wrong on them, but they choose not to make you salvation depend on it) really prove?
Still, just because one leader and ministry (Martin/CRI, and the ministries he lists in the book as saying they're not a cult) declares a group not a cult doesn't mean the group's teachings are right. For that would be to essentially assign to that ministry and leaders the ultimate authority in truth. Like what they declare as true or not means so much, and proves your group is true. Those same authorities still say Sunday, eternal Hell and non-kosker diet are the true Christian beliefs, and you believe they're wrong on those points, so what does them saying SDA is not a cult because of them (i.e. you're wrong on them, but they choose not to make you salvation depend on it) really prove?