We booked the 2-berth cabin on VicSapa from Hanoi to Sapa and we did not regret it! It was cosy and clean. The bed was comfortable enough and the blankets were warm, which was needed as the aircon was cold and could not be turned down (we just turned it to face away). There were snacks and drinks provided on our cabin table. Toilets were clean. No shower on board but we managed to reach out to a hotel we booked later in the week and they allowed us to shower at their facilities. This trip was unlike any of the horror stories I had heard. It was actually the opposite and we managed to get sleep for most of the night. The train does shake but it is not as bad as I thought it would be. This was such a fun experience, definitely worth doing once!

Review Link: https://www.tripadvisor.com/Attraction_Review-g311304-d25070205-Reviews-VIC_SAPA_TRAIN-Sapa_Lao_Cai_Province.html