Well I use the PRVI as main card, unless Amex is not accepted. I use it overseas as well, and yes I know, the exchange rate and rounding is not the best on the market but honestly, I don't want to juggle with 15 different cards in my wallet, these two are more than enough.
Not sure what you want to know regarding issues...? It's just a simple Amex card
The limo service is not bad, used it a few times so far and every time I got one of those white Mercedes that comes and pick me up. Saves a good $20-30 depending on where you stay on the island.