The concierge is not but not really necessary. We took advantage of the early boarding, the concierge meeting and a few other tasks during the cruise. We also ordered full breakfast each morning to our suite.
The reason we book the Cat 3 is the room. While 2 connecting Cat 6 or Cat 9 will give about the same space, the Cat 3 suites are still much nicer.
We book far enough in advance to get on of the four midship Cat 3 suites with the triple wide verandah and larger living room.
The suite also has a nice round dinning table for eating on and we also use it for kids activities, making notes, etc.
There is also a wet bar.
The living room has a TV, stereo, CD player, and VCR (borrow CD and tapes from concierge).
Master bath has a full size jacuzzi tub, separate shower, huge walk in closet, make up desk area, and double vanity.
There is also a separate bath room with a shower off the living room.
Tons of storage space.
Plenty of room in the living room even with the sofa bed out.
The suite is beautifully decorated and has fantastic woodwork.
If money is not really the issue, my preference would be to go for one Cat 3 instead of 2 other connecting rooms.