We are all humans!!
Of course people of different cultures will have similarities, in this case Haiti and the Dominican Republic, we are all humans. However, its the little difference that make the big difference in the cross cultural aspect of things. Haiti and the Dominican Republic are as much alike as they are different.
"Likeness" (sorry for inventing this word) between Haiti and the DR include same island, similar history, and some other minor stuffs like the passion for cockfighting in both countries, etc.
The differences are what make each country what it is, otherwise the entire island would have been one unified country, right!
Haiti speaks French-creole, have a very strong african element in it's culture (the most africanize country outside of Africa), its something like 99%black with the 1% left being mulattos, have about 3/4 of its population in abject poverty and about 28% in "normal" poverty with the rest being super rich. Smallest economy in the hemisphere and it has been shrinking non stop since 1997, and many other.
Dominican Republic speaks Spanish, have a very strong european element in it's culture, its 3/4 mulattos, 16% white, and the rest blacks (excluding Haitians in the DR), have about 8% of its population in abject poverty and about 52% in "normal" poverty with half those getting weekly checks from family in NYC, 30% are middle class, and 10% rich. It has the largest economy in the Central American/Caribbean reagion, the largest tourist industry in the Caribbean and growing, love of baseball, and many other.
My point is this, when people want to find similarities between cultures, they will always find them because we are all (the entire planets homosapiens) are all humans. However, its the minor similarities that makes the millions of cultures, hundreds of countries, billions of individuals who they are.
And about my opinion on the Haitian thing in the DR, yes, it is a problem that will only get worst. The best thing happening from abroad towards Hispaniola is that project sponsored by the European Union for creating free-trade zones along the border, other than that it's a sad landscape. Haiti has always been seen (and probably is) a threat to anything dominican. In the past it was a life or death deal with constant bloody invasions, today its a cultural deal. The Dominican culture is one that can be very easily influenced by outsiders, the more Haitians enter the DR, the more Haitianize the DR will become and the less Dominicanidad will survive. With this in mind, it is safe to say that the economic stability, cultural vitality, and overall sovereignity of the Dominican Republic is under threat from Haiti over the long run. In my opinion, the only thing that would create the U.S. and Europe to reconsider their "let the DR and Haiti doom each other" plan is to increase the amount of either white or well off people in the DR and/or Haiti. It would be ideal if the white/affluent number of people would increase. I am a strong believer that race is still a major player in decisions worldwide and that money is a close second. Lets not be oblivious to reality, this is the truth.
Other than that, the DR is doomed. Of course, if I keep rambling on I could also say that Puerto Rico could see its stability threatened in the long run too. The poorer Haiti gets, the more will cross into the DR. The more in the DR, the poorer the DR gets, the more will swim to PR. The more enter PR, the darker and poorer PR will get, the more incentives for the U.S. to either ditch PR, otherwise this problem will infiltrate into the American mainland and uncle Sam don't want that, because if Mainland USA was under any uncontrollable threat from Haiti's economy disaster, the USA would have been shifting the billions of dollars of aid to Haiti and made sure that capitalism survives in Haiti. But since that is not the case, for now at least, the U.S. is not interested in such proposal, so the brunt falls on the DR. These are my 2cents into this aspect. Feel free to either praise me or criticize, but please don't offend, thank you in advance.