Seventh-day Adventists actually can be categorized quite nicely into conservative evangelicalism. They step outside the mainstream on issues like the weekly sabbath, the state of the dead and by maintaining a historicist approach to prophetic interpretation. They also have an unusually strong emphasis on religious liberty and the separation of church and state. But their soteriology/christology/etc... tend to be very orthodox evangelical.
Source: Grew up Adventist, still am a practicing Adventist, MA in Religion, and I read the work of many non-Adventist theologians and scholars.