I stayed here for three nights as a Gold. In short, it was adequate. I might stay again, but I might not.
I booked and received a Mystical Single -- no upgrade. The size of the room was fine (small, but I knew that), but the use of space was particularly frustrating. There was no desk (a sore spot for the Marriott folks
), just a movable podium large enough for a laptop. There would have been plenty of room for a desk -- a low cabinet mostly holding the minibar took up a disproportionate amount of space. No coffee/tea service in room, though I think they had coffee in the lobby available during the day.
My "limited SPG benefits" should have included two bottles of water daily, but only included one, and only two days. (I didn't push the point because I don't actually care about the water bottles... just mentioning it since some people do.)
The gym was adequate (above average by European standards, but not fancy), and my breakfast experience matches the above posts.
Regarding the train from the airport, you can pick up the #3 or #6 tram from directly in front of the train station and take it two stops to directly in front of the hotel. If your airport ticket is still valid no additional fare is required.