The place is as great as it looks in the pictures. It's located in the middle of old town in short walking distance from the main train and bus stations as well as a bus stop from where the buses to the airport go directly.
One note for people with restricted moblity: The flat is on one of the upper storeys of an old house (as you can see from one of the photos given).
For us, it was a perfect base to explore Riga's old town, parks and Art Nouveau quarters. We only stayes one night, but would have stayed longer if we could. We're likely to be back!