We stayed here for a week in July 2011. We upgraded to the "Club Floor" principally because breakfast, together with general use of the Club Lounge, is then included in the price. The upgrade cost was approx. £400 for the week for two of us. As breakfast in the hotel is normally about £29 each per day, the upgrade did not actually cost much more than the breakfasts would otherwise have cost and effectively meant all the other advantages of the Club Floor were then effectively "free".
Our room on this floor was very nicely, and quite recently, fitted out, with a recent bathroom including a walk-in shower. The room was a good size with a sitting area and tea and coffee making facilities.
Breakfast was then taken in the Club Lounge, and was the usual buffet selection. There was a cooked option - this was nice but consisted of the same choice of scrambled eggs, hash browns and bacon each morning so got a bit monotonous.
The Club lounge had free internet access, with tea/coffee, soft drinks, and cold snacks available all day. But from 5.30 pm until 7.30 pm each day, they have a much wider choice of more substantial snacks, including a choice of two hot snacks ( which were different every day ), and wine/champagne/beer all at no further charge. We found this was sufficient to make a reasonable light meal in itself and definitely makes the upgrade worthwhile.
The lounge is, however, a bit on the small side and on occasions there may not be a spare table available.
Our room looked onto the internal quadrangle, an upgrade was available to a room with a view but that would have been about another £300 for the week so we declined.
We had very little contact with the staff during our stay, but those we dealt with were very pleasant and helpful and spoke excellent English. The reception desk had, however, lost the pre-paid accomodation voucher we had handed in on arrival, so it could have been rather embarrassing if we had not kept an extra copy !
The hotel itself is very conveniently situated, about 10 minutes walk from the Central Station ( and the Arlanda Express train station ) and about 5 minutes walk from either the old town ( Gamla Stan ) or the main modern shopping area and about 15 minutes walk to the ferry terminals.
We enjoyed our stay there, and for the above reasons, would definitely reccommend the upgrade.