I stayed 5 days at this hotel in a single economy room and I must admit that It's a very impressive hotel. Due to the location though I highly recommend getting an SL Access card. http://sl.se/en/fares--tickets/
To get to the hotel all you need to do is take the Blue bus (No.2) from Slussen to Ersta Sjukhus.
The hotel is beautiful, the grounds are beautiful, the hotel room was very nice, the facilities are great, en-suite, flat screen TV, WiFi, A very nice hotel all-in-all.
My only slight negative is the staff, It's nothing serious at all and the staff did help me whenever I required it but I didn't exactly feel welcomed as a guest, maybe it's because this hotel is a 'conference center' and they have to deal with so many people that the staff can't add any warmth, I felt a definite coldness that I didn't really experience anywhere else during my stay in Stockholm.
This hotel is based in what I can only describe as a Christian compound and at 11:00AM a bell rings calling people to a little church. (You don't have to go, lol)
One thing that made me leap out of bed on one random morning was the sound of a ferry's horn, the ferry terminal is practically next door and at about 6:30 I was awoken to BAWOAWWWW! (Made me laugh)
There's a supermarket and a 24 hour convenience store close by which is always nice, at the convenience store you can top up your travel card.
Breakfast at the hotel isn't good, can't cook a hard boiled egg competently and it's only open until 8:00AM. :(