I lived in northern Uganda for a while with my kids - for research. There are A LOT of Westerners living in northern Uganda (NGOs, but largely missionaries). Whenever I go, it seems that half of my flight's passengers are going on a missionary trip. When we were living there, the only other Western kids my kids' age, were the missionary kids. So we got to know some of them really well. These are families who are living there with different purposes. It was always the men doing the actual missionary work, the wives were at home, homeschooling and cooking.
One husband is a minister and was building a church, while temporarily holding church in a big tent that looks likes a circus tent. His goal was to develop a kind of ministry school in the north. They brought an entire shipping container of their American lives and built an American home - it was sooooo bizarre to walk in and see lazy boy chairs and wallpaper and wallpaper borders and paper towels and classic round dining table and chairs. They kept their house airtight and air conditioned. It was like walking into suburban America... so bizarre. (You can get the most beautfiul handmade mohagony furniture there for dirt cheap). The poor wife seemed miserable and it seemed to me like she felt she was sacrificing herself to be there.
Two other husbands have since moved up to S Sudan with their families - they had spent 2 years in N Ug waiting for their S Sudan home to be built. They are a 'team' from the same church. They spent those 2 years developing a plan for how best they can help the local people where they are moving to. Last I heard they were going to help them with agriculture, somehow. They were all lovely people and very gentle with their religion and shared a lot with their local neighbours and learned the language and food.
The 4th family we got to know were the most extreme. The husband was there to preach and convert. When we first arrived he took us to get a hotel and the woman at the desk had typhoid. He put his hand on her head and made some very dramatic and elaborate preach about exocising the demons from her and when he was done, he told her she was cured. She went along with it but later kind of smiled (not believing) when we asked her if he had cured her. He went around town preaching and they held a Sunday service where he preached more. They had regular mission teams come to help him - some for a couple of weeks, some for longer. These missions included 15-20 people, usually college students. He would send them out throughout the north where they would go and preach and convert. I don't really understand how this worked because none of the college kids spoke the local language, obviously. But this guy kept me with his wife so I didn't get to ask too many questions. She complained about the local food and people and they did not like to go into town or mix with local people. We once had some of my friends' kids for a sleepover (locals) and they flipped when we told them.
Then there were the packs and packs of other mission trippers. There were so many American college kids roaming the streets and you hear 'Jesus' and 'the Lord' non-stop coming from their mouths. It's exhausting. It's ridiculous. Often locals use the missionaries as much as they can for whatever incentives they offer - food, clothing, healthcare, etc. I see on indiegogo.com so many people raising funds to get them sent over on missions. So little of their money is actually put into the local economy. So few of them treat the local people as if they are intelligent adults worthy of respect. These college kids coming over and thinking they are going help these poor misguided African folk. Drives me nuts.
There is a devastating effect to all of this. Here's a big one: http://www.godlovesuganda.com/film/ And another one: http://callmekuchu.com/
A few others not raised so much in those films: Dependency, distrust of local ways and beliefs (which are practical and relevant to THEIR needs and experiences and land), trust in imported ideas and ways (which often do not work in their context), and paternalizing an entire population, not to mention creating a sense of moral superiority in these college kids who are actually doing nothing more than getting their kicks from someone else's misery. Ok, that's a little harsh, but that's my general sentiment.
All that being said, I do believe there are missionaries who do work with local people as equals with dignity and who become part of the community and who do offer them whatever they can to help and to give hope and friendship without expecting glamour and a sense of moral fulfillment in return. These are people who build lasting relationships with the people in their communities - they don't just go and take pictures of themselves with cute little African babies and then leave forever. The good ones don't preach, but they care and love and support and listen. They do what they can and don't presume they know best.
Ok, rant over. This is a hot topic for mer :)