I've heard all the isoms are fakes there. When I was there, I was near Santo Domingo, I saw my share of glasstops...
Most of the cigars are produced for export, so they are expensive/ hard to find there. Thats what I heard/read about anyways. The airport I was at in punta cana had a decent humidor, the prices were nothing spectacular though and there wasn't much variety. They had Davidoffs, AVOs, RyJ, MC DR and ISOM from what I remember.