They are nothing alike. I was a member of the Mormon Church in the 1980's. They believe in John Smith and the Book of Mormon. The believe in baptism by proxy and other rituals. I attended a Pentecostal church in the last 8 years and they believe in the fruits of the Spirit, including speaking in tongues. They follow the Bible and no other book unlike the Mormons. There are too many differences to list them all, but here was a few.