We stayed at the Man-Tess in Riga for 6 nights in August. Taxi from the airport was easy after giving the driver the address. (you can take a bus and walk, but you'd need to be good at directions since it's a bit winding in old town.) It was late at night when we arrived, but somebody is on duty 24 hours - the front door is locked at night, but a buzzer alerts the night person to let you in. Good security. There is an elevator so you don't have to carry luggage upstairs.
Man-Tess is in Vecriga, the old town. It is close to the canal and the Art Nouveau area of town too. Easy to walk to all the attractions in old town and other areas too.
The price is good, breakfast is included and open for a long time every morning. Very good breakfast, coffee made to order. Always cereal, toast, pastries, cheese and meats, fruit, hard boiled eggs.
We left and came back, so we experienced two rooms. On the 4th floor, facing the side street rather than the front, we had a nice large room with a comfortable bed and good bathroom, nothing fancy but fine. It was still a bit noisy at night with street noise. The windows open for a breeze - it was hot, but not too hot. When we returned, we stayed in a room on the 2nd floor, facing front. It was smaller, but we hadn't booked it in advance and it was available. The problem with sleeping in front is that the bar down the street is very rowdy at night, all night. Difficult to sleep with noise. Stay on the side if possible.