Kathy, that "few thousand" can make a difference in whether you get an extra vacation! Just decide whether the cabin size makes a difference. Marc did a great analysis above, and to get to RSSC standard balcony suite, it is clear you have to go to PH to get a little bit bigger cabin from Mariner.

Once you decide on cabin requirements, its just a matter of what you'd spend at the bar, for water, etc, and tips, and then the value of all the other amenities that you would pay for on Oceania. I think you should try it if it fits an extra vacation in the year!