It's definitely a good idea to learn what different people believe and why because either you could learn something and improve yourself... or learn something about others to help you help them. As with any group, it's hard to get a fair representation of a viewpoint without talking to some people who hold that viewpoint. People with an outsider's perspective tend not to give the fairest of representations, whether they want to or not.
But, I can try to list the primary thing that differentiates them from mainstream Christianity:
-Primarily, they are non-trinitarians. They do believe Jesus is the messiah and the son of God, but they view him as a unique being, rather than part of a trinity.
-I've seen some people say they "reject the cross" ... but they agree in most other details of Jesus' death... but they consider what he died on irrelevant, and consider the use of crosses as a holy symbol as bordering on idolotry.
-Another primary difference is that they believe that humans were designed to live in eden and thus do not go to heaven or hell at the time of death. They believe in a heaven that angels live in, and a pit where demons either are or will be chained (not sure on that one), but that humans have no place in either. Rather, they look forward to Armageddon, when God retakes the earth, restores it to a Eden like state, and brings those who have died back to life.
- They're big on using the name Jehovah to describe the Father, taken from the KJV translation of YHWH. That one I actually really respect. Jeremiah 16:21 has never sat well with me as God himself speaks about how my his power and might people will know that his name is (redacted).
-They avoid any holidays with origins they consider questionable.
-Their emphasis on ministry starts on day 1. They have an ongoing ministry school for everyone, regardless of age... children old enough to read are offered chances to read bible passages in front of the congregation and given types on public speaking. Also, everyone baptized are automatically considered official ministers.
There's some lesser known differences that aren't particularly "good or bad" ... just differences.