Been to:
Barbados – nice island but I found it very expensive 🙁
Grenada – Got married there 🙂 very quiet & relaxed – nice island 🙂
Trinidad – nice but very scary/violent place – avoid 🙁
Tobago – very cheap but not overly commercialised – will deffo go back & I would happily recommend it to you for your first visit to the Caribbean 🙂 🙂