I currently have a D1 - deck 10 booked in the aft of the Mariner. I am seriously considering switching ot either a Cat C or Cat B... just for the luxury of space. Right now the only thing available is side cabins. Am I nuts to give up the aft balcony? I just think it might be fun to even try the Cat B for concierge... what the heck!!
If I had a choice of a D1 aft cabin and a B, I would definitely take the B. It is larger, very attractive i.e. marble bar, larger bath, and conceirge.
We've had four (royal family suites) aft cabins and love it back there also. Of course the balconies w/ the RFS's are huge but being that it's a "family" suite, it's not appointed as well as a B or better. We're getting a side suite on the aboard Mariner in Nov. Am looking forward to feeling pampered.
I just had a B Suite on the Navigator, and it is nicely appointed and larger, but really, not a lot larger. The on line videos and pictures make it look a lot bigger than it is. The best part about it is the bathroom with the tub and marble all over. The balcony was very long, but of course not very deep. It was large enough for one lounger, a table and two chairs. The concierge service is really nice though, I will admit that.
In terms of a decision, its really a matter of the extra money and whether you want the little extra space, the great bathroom or a bigger balcony. One other downside, after being in a B suite, it is sort of hard to picture yourself having to move back to a D cabin or an inside. You get sort of spoiled ;-).