This Sapa express sleeping bus is one of the best sleeper buses I’ve taken. We were on Bus #10, which left the Hanoi office by 10+pm. Each person had an individual berth/bed for the journey. There was also free WIFI on the bus. The service was very professional, a guide would introduce himself & the bus captain, and give a brief description (like what time we’ll arrive at Sapa, what time will the bus leave the next day, where is the meeting point, etc.
Remember to wear comfy clothes coz you’ll be sleeping in them), and it might be cold at night. Each traveler also had a bottle of water and a small snack.
Source: Yptay / Singapore – TripAdvisor