We just took those flights for our cruise last week, and the service was great. Although the food seemed a lot better on the way there, as you are spoiled on the PG!
Our flight was a little late getting into PPT, and they only have 2 people processing customs for non-EU folks, so try to get to the front of the line once you get off in PPT. There also seemed to be a bit of confusion (and short delay) in the transfer to the Raddison, but things worked out fine. It was nearly 2am before getting into the hotel room, as it's about a 20-30 minute drive from the airport.
On the return flight, we arrived at JFK an hour or so late, and again clearing customs takes a bit, so leave plenty of time for any connecting flight (you won't be concerned about this, but others may be connecting). We booked the 7pm back to DC from JFK, and just missed the 4:30, so we're glad we booked the later flight. Also, be aware that the return flight leaves from PPT at 21:05 (or 21:15), but the transfer from the hotel leaves at 17:50, so you only have 3 hours at most in the room / around the pool at the Raddison. There's not much in the way of food at the airport in PPT once you get through security, so bring some or be prepared to buy some candy bars in Duty Free!
All in all, for $899 a person, I was very happy with the flight, transfers, etc. The Raddison is a great hotel with a nice beach and sweet pool, and this package (while not a true pre-post stay) was just enough so that we were able to enjoy Sat. night and Sunday on the PG without having just arrived before boarding.
-Kevin