Lived on Boat in DR for Years
My wife and I came to the DR via sailboat in 1986 and lived aboard in Samana harbor until we left to finish our cruise of the Caribbean in early 1997. Boat is again anchored in Samana harbor, but since August have been living in a condo we purchased in Sosua.
Regarding price/quality/selection of a boat, you are generally better off making the purchase in the US and bringing it here. However, you can check with Captain Forrest Rodriguez to see what is available. He would be the most knowledgeable about the boat market in the DR. He can be reached at Centro Marino del Mar in Boca Chica (tel. 809-523-6033) (fax 809-523-6923). He has an e-mail address, but I can't seem to find it. You should also talk with him about marina possibilities on the south coast and he is involved in their operation.
If you are going to be living on the north coast, then your choices are anchoring either in Samana or Luperon harbor. There are no marinas at present on the north coast. Anchoring the boat in some other area, Sosua, for example, is not an option. There are designated harbors in the Dominican Republic and they are very strictly enforced. There are also rules and regulations on boat use that you would need to become accustomed to. You can enjoy your boat, but before leaving the harbor you must always clear out with Port Commandante. One reason for this is the desire to insure that the boat isn't leaving with a load of Dominicans trying to sneak into Puerto Rico. If a boat leaves harbor without clearing out, the Navy will be sent to investigate. Look on this not as an inconvenience but as protection against having your boat stolen/hijacked.
If you would like to discuss this further, please email me direct. The subject of boats/boating in the Dominican Republic is really too complicated to do justice in the message board.