We were in Sky Suite 6145. It was about the size of a standard hotel room, which is large for a ship, since it serves as extra bedroom for the Penthouse, and thus has Penthouse-level appointments. The cabin features a nice, wide balcony with partitions which easily opened to balcony next door (and could have opened to Penthouse too). This worked very well for us, since fellow members of our group were staying next door in room 6143 (a Concierge Class room). The balcony has no cover, so there is no privacy to be had and in the event of rain or high wind/mist we found it unusable. Even so, when the weather was nice (especially during our dramatically-close approach to Hubbard Glacier), we found ti a huge asset for the cabin.
The room has a flat-screen TV that worked well once we realized we had to turn off the VCR. It also features a sofa that I assume folded out into a bed. There is no dresser in the room, just a closet. The closet has two sides, each 2.5 feet wide. One side had a closet rod, the other side had three shelves, although the safe takes up half of the middle shelf. The light only worked on one side of the closet.
Another great feature for this stateroom is the huge bathroom. It was done up with lovely dark-marble tile (although several of the tiles were cracked). The shower was big enough for two people and it also has a standard-size bathtub. There is a dual vanity with two medicine cabinets (we only found out the mirrors swung open on last day of cruise). There is an in-wall hair dryer and a standard consumer hair dryer stowed under the sinks.
The fit and finish of the room was nice on the surface, but there were enough dings and scratches to give the feeling of an opulent hotel gone slightly to seed. I assume this will be addressed when the Millennium goes in for its solsticization next year.