We stayed at the Valdemars at the end of January and enjoyed our experience. The downsides: Room size - very small, but nice. Two single beds instead of double and cold showers! We asked to be moved to a double room and were told none were available.
On a more positive note the hotel is lovely, staff were very friendly and helpful and the breakfast buffet and bar food were delicious. (scrambled egg at breakfast is amazing)
We didn't eat at the resturaunt but heard it was lovely.
Part of the hotel is undergoing renovation, seemingly being converted into apartments.
There isn't a whole lot to see in Riga so we took a train to nearby Jurmala for the day and had a lovely walk along the beach.
Very nice and quiet hotel just outside the Old City, about 5-10 minutes walk. Brekafast buffet was great! And the staff was very helpful and nice. Also a nice surprise was when we got there that they had a little sauna/steam room and a jacuzzi that was free of charge for the hotel guests.