Stayed 3 nights here and had a wonderful time. I booked two rooms, one a suite ("Titanium") for myself/wife/kid, and the other a "Larger Gold" (for parents). The property proactively upgraded the second room to a Titanium as well -- very similar but slightly smaller than ours. (Ours, the larger one, was on the 4th floor; the smaller one was on the 5th floor.)

Agree with the comments about front desk being a little impersonal/aloof, but by no means impolite. We used the hotel's transfer service for our arrival which was a reasonable 370 RON for a V-Class van including a child seat -- and the driver was excellent. We were all offered sparkling wine upon arrival. I was told that breakfast would be included for one room only, so we had to pay 20 euro/person for parents to have breakfast, but it was worth it for us all to be able to eat together. (Breakfast is 25/person, but 20 if you add it at check-in for all days.) Breakfast spread was nice, omelet station was good, and several dishes from the kitchen were available, along with self-serve sparkling wine.

The spa/pool area is very nice and relaxing, and my wife says the massage was excellent.

Location is fabulous, you're walkable from everything but you're just far enough from the chaos of old town that the noise isn't an issue (maybe it would be if you're a light sleeper... but our 2 year old slept just fine).

For our last full day, I picked up a rental car (I used Sixt at the Radisson) and we drove up to Peleș Castle, then did the gondola ride at Sinaia, and then went to Therme on the way back in -- a wonderfully packed day. Therme is the coolest water park I've ever seen, and it's like a water paradise for adults and kids alike. We were able to then drop off the rental car at the airport before our flight out the next morning, easy peasy.

I don't foresee another trip to Bucharest specifically in the near future (I would love to road-trip across eastern Europe and see smaller places) -- but I can heartily recommend the Marmorosch and would return if I stayed in the city again.