The common factor between all religions is faith. All that changes is the order the ingredients are mixed and the presentation of the final product. One religion may say they are true because they uniquely have men who dance in skirts, another claims they are true because they cannibalise human flesh , another claims it is true because they have new scripture and so on. Coming to this site and reading about how people feel, what the day to day consequences of faith are and how supernatural beliefs make people talk and think a certain way was fundamental in helping me see how similar we all are. I think Mormonism and Witnesses are cut from the same cloth simply because they are a product of the same culture albeit separated by a few decades. They have different peripheral doctrines and practices that are open to change ( revelation or new light) that the members mistake as core doctrines but both have the same core doctrines that the members accept but don't think about as the real heart of the faith ( unquestionable authority in the hands of a self appointed few).
I was at first dismayed and then glad to see the same real experiences simply dressed in different terminology between the two faiths as expressed here. People talked of the demands to put church before family and self by attending meetings, reaching out for responsibility, the boredom of having the same bland material each meeting, the human cost of placing untrained men in charge of others lives on such matters as relationships, social activities, gender preference, finance, approved media, clothing, medical matters, bereavement and loss counselling, punishment and so on. I found the words of encouragement ( wait on Jehovah / endure to the end) ,constraint ( don't run faster than Jehovah's chariot / follow the prophet ) and excuses for failure ( over zealous brethren / sometimes the prophet speaks as a man ) all identical in meaning but using different group buzz words.
The effects of both faiths are similar , both provide roles that allow certain people to experience high levels of influence and control, both do improve certain peoples lifestyles ( those in need of strong social support and peer pressure to avoid self harming habits like drugs), they do geberally provide comfort in times of grief, they give structure to behaviour, they induce feelings of devotion, euphoria and a strong sense of self improvement but at the cost of seeping, unrelenting guilt, the rejection of 'the world' and the handing over of self to group ( you no longer have full rights to your mind and body.)
Lastly I want to note what they do that is very, very wrong and both are culpable of. They present themselves as the ultimate source of knowledge. This has allowed them to make dangerous medical advice ( no blood / gay electro shock therapy) , to make immoral social advice ( no gay marriage / no interracial marriage ) , to lie to whomever they need to ( theocratic warfare / lying for the Lord ), to support bad science ( flood / Indians are Israelites ), to suppress education ( evolution ) , to create arbitrary rules with huge social consequences ( military service / polygamy ) , to indulge and protect the human frailties of the leaders while condemning it in the flock ( excessive drinking / adultery ) , to waste the money of its members in non charitable ways ( Beth Sarim / City Creek ) but above all to nullify thought and deny members the right to seek out knowledge from all sources - they replace scientific thought and process with blind faith and trust in the structure.
TL:DR Doctrines , words, rituals may be different but effects on the mind , members and in day to day practice are the same.