We have enjoyed our stay at Nicola's place. It is a spacious, clean and quiet flat. The location couldn't possible be better for exploring Riga on foot: right next to the main axis through the old town, just metres away from the Laima Clock and the Freedom Monument. It takes perhaps 15 minutes to walk to the Art Nouveau quarter in one direction, 10 minutes to the train station and the bus terminal in the opposite direction.
The flat doesn't offer any views across the city because it faces an inner courtyard on the roof, but that is in fact a blessing because it shelters the flat from the noise of partying in the old city, which can be considerable, especially on a weekend.
The flat is equipped adequately, though not lavishly. We didn't think it was particularly cozy, but perfectly fine for a stay of a couple of days. The second bathroom, in the back, is lovely and quite a treat. This is a commercial rather than a private rental, managed professionally by Nicola's company, along with a bunch of others in the same house and elsewhere in the city.
In a nutshell, it is a fine place and I can recommend staying there.