Yeah, of course Haiti is not a lot like Dominican Republic, but it probably is the most similar taking into account demographics, geography, culture, technology and politics. I think you are discounting the fact that Haiti is also a lot of things different from African countries too. Most notably geography. Bottom line is Haiti is pretty unique.
Dominican Republic is not similar to Haiti at all. Not even close.
Dominican Rep., most similar to Haiti?, I'm dominican, and I know about Haiti. Western/Central African countries are the ones most similar to Haiti. The other side of Hispaniola is extremely different from us. Even the maternal/ paternal african lineages between both nations, are different in origin. Please educate yourself people, and don't automatically assume things based on geography.