We have stayed at both. Ron Jon's rocks! Beautiful themed pool, a mini-waterpark, lazy river, etc. Small putt-putt course, a movie theatre, game room, etc. The rooms are beautiful and new.
Radisson, nice, a little dated, rooms are comfortable and overall it's fine for a night's stay.
The biggest difference between the two, price! Ron Jon's is usually 50. - 100. more a night. Oh, the Radisson offers a free shuttle to port, Ron Jon we had to pay 3.00 pp. Hope that helps a little...