Seventh-day Adventists are very much like most other protestant Christians, sharing the same core beliefs that have shaped the Christian Church since its very beginning, including the very good news that we are saved by grace through faith - and this as God's gift to us through Jesus..
There are, however, a few unique contributions that we believe Adventists make to the larger body of Christ, and it is in the sharing of these that we have a unique purpose. Among those are these:
THE EXPERIENCE OF SABBATH. Not only do Adventists observe Sabbath on the seventh-day of the week (in continuity with the experience of God's people from their earliest recorded memories), but we also seek to take seriously both the great realities of life that Sabbath celebrates (God as our Creator and Redeemer) and the kind of life that it encourages us to live (one that reminds us as we set aside work, that our core identity is not found in what we do or produce, but in being children of a loving God - and of course, that we need to treat others the same way).
THE WHOLENESS OF PEOPLE. In contrast to the Greek idea that has influenced many Christian thinkers down through the ages, (that we are "spirits" or "souls" that inhabit bodies), we believe that we are indeed "whole" people, with all the various aspects of our lives (physical, mental, emotional, relational, etc.) interconnected and inseparable. We don't just have bodies, we are bodies (without a separate full consciousness apart from a real physical existence). As "whole" beings, we believe God wants to bring health to all aspects of our lives, and so Adventists have invested a lot of time and energy into medical work, education and missions (including improving the living conditions of others) as well as sharing the story of the gospel.
ANTICIPATION. We also share the New Testament hope of the Second Coming of Jesus (thus the "Adventist" part of our name), the resurrection and an earth restored to what God intended for it. It is at that time that we also look forward to a final resolution of the problem of sin, and a universe restored. But even as we look forward in joyful anticipation to that time, and share that anticipation with others, we do not simply wait, but rather work to bring into the present as much as we can of the life that we will experience then. Even now we can begin to embody the life of the Kingdom of God, and be a presence that encourages peace and healing in our world.
There are of course other things we could mention as well, but these are some of the ones for which we are best known. If you would like to learn more, we would be happy to talk with you.