I wonder how much of the cleanliness you've noticed is due to these churches being controlled from other countries. When I worked in the Dominican Republic, Small evangelistic churches were kept up about as well as any lower-class home. The big catholic churches, at least outside the biggest cities, had the look of having been beautiful once, but having fallen into disrepair (cracked bell, flaking paint, smashed windows, sloppy repairs, you get the idea). Once you got to protestant churches that were run by americans or europeans, they were always imaculate, as were the LDS churches.
*thinks* no, it must not be the american influence. The Jehovas Witnesses had crappy churches too. At least in the small towns I visited.
"I wonder how much of the cleanliness you've noticed is due to these churches being controlled from other countries."
I don't know what it is you mean by 'controlled from other countries'. Local clergy are called from local residents with very, very few exceptions. Missionaries are often from another country, but they are not part of the church leadership.
Anyway, even in North America most of the building maintainance and cleaning is done on a volunteer basis by local members. If LDS buildings in that area stand out, the local members deserve the credit for it.