@David1967 thanks to
@Lyndon for his information on SDA's.
I guess the main differences would be....
1) Observance of the Sabbath, since we see no directive for Gentile Christians to observe what was essentially a Jewish law. It was not included in the "necessary things" listed for them. (Acts15:28-29)
2) We will remain politically neutral which means we will not vote in elections and have no political aspirations or affiliations, seeing the political world as being under the control of the devil (1 John 5:19)
3) We don't dictate dietary requirements except for what is stated in the Bible. We can choose whatever is acceptable to ourselves without judging one another. There is no prohibition on eating meat, just as long as the animal is humanely killed and properly bled. (Genesis 9:3-4) And since gluttony is an indication of loss of self control, we would not want to consume any sort of food in a greedy fashion.
We can drink alcohol but never to the point of drunkenness. All things in moderation is a good motto.
We do not smoke or deliberately damage our health with illicit drugs, but are all free to choose whatever health regime is appropriate for Christians where we live, being careful to avoid spiritistic practices that accompany some alternative health regimes.
4) We have no "founder" as a prophet or with any special gifts. There was a group of men in the late 1800's who came together from several religious denominations, who all recognised that Christendom was not teaching what Christ did. They set out on a quest for Biblical truth by examining every doctrine of the church in light of the scriptures. One by one the doctrines that were introduced early in church history were tested and eliminated. Charles Taze Russell was the group's spokesman and financier, dedicating his life to finding the truth. His expose' of Christendom's doctrines gained him many enemies. His public debates with prominent clergy demonstrated that he could back up everything he said with scripture. People sat up and took notice and a groundswell of interest began.
Consequently, we see ourselves as no part of Christendom at all, having no core doctrines in common with them.
5) JW's are known for their preaching work, which was a commission from the Christ. We see no way to call ourselves Christians and yet neglect a direct command from our Lord. People's lives depended on it. (Matthew 28:19-20) The good news of the Kingdom had to be 'preached in all the world for a witness to all the nations' before the end of the present age. (Matthew 24:14) Jesus said it would be done with his backing and we see no other Christian group preaching, not just in overseas missionary work, but in our own neighborhoods. Everyone was to be given opportunity to hear the message and to make choices.
6) We will not tolerate homosexuality in our ranks. This is against God's law and there is no way to excuse or to justify SSM among our members. This makes us unpopular with many in today's world, but we will not tolerate immorality no matter the gender.
We have gay people in our congregations, but they are celibate. This is their sacrifice to God in obedience to his laws. Sexual orientation is not a choice, but immoral sexual activity is.
7) We have no "clergy". The "shepherds" in our congregations are always male, because in God's headship arrangement, women play a support role, not a leadership role. We are very happy with this arrangement so there are no women sitting in our Kingdom Halls with aspirations of becoming shepherds. We have a body of elders, rather than just one "pastor". No one man gets to make choices for the flock. The "body" act collectively to ensure unity and peace with the global brotherhood. We all believe the same things and worship the same way.
All of Jehovah' Witnesses are "ministers" in the sense that all are under obligation to preach and to teach as Jesus commanded. So no one is left feeling that they want to be anything other than what they are...."Christians" fulfilling the roles assigned to them from God. Males teach in the congregation, whilst women teach in their public ministry.
8) Our approach to Bible prophesy is that we take it very seriously. Prophesy is a fascinating topic as we see it unfolding with more understanding of its features as time goes on. (Proverbs 4:18) It is only ever confirmed with the benefit of hindsight, however.
We see ourselves as being deep into "the time of the end" spoken about by Daniel and reconfirmed in John's Revelation. The features of the sign Jesus gave to indicate that he was ruling, we believe is very evident. (Matthew 24:3-14)
The lid is being lifted on how corrupt this world system really is, greedily exploiting people's ignorance and carefully managing their perceptions about everything to fool them into supporting a system that is dedicated to milking them of their money, their health and their spirituality.....it is a complete mess!
The good news is....we believe that God is going to bring it all to its foretold and anticipated conclusion. We understand that what God began in Eden was derailed by an abuse of free will.....God responded by allowing humans to experience the full consequences of their actions and to see for themselves that life without God results in the world we have now. It doesn't work because everyone is looking out for themselves. Love is dead, and selfish concerns drive everything. This world has to go so that God's will can be done "on earth as it is in heaven".
That is the basics of it I think. Feel free to ask any questions.