Excellent overnight bus trip from Hoi An to Da Lat with Viet Lao. The staff was very friendly, the bus was clean, the driver was a good driver, and there was no music or unpleasant noise. All this at a good price with smooth communication in English, so I recommend it. For first-timers: there are no toilets, but there were three stops approximately every two hours (you are notified in advance by announcement). You cannot eat on the bus, but there are restaurants and snack bars at some stops. You must remove your shoes and walk barefoot. At the stops, plastic slippers are provided as you exit the bus; you return them to a bin before reboarding. A small bottle of water, a blanket, and a pillow are provided. There is a USB port. I couldn't get the Wi-Fi to work, but that might be my fault. For those who are overweight or very tall, I recommend taking buses with fewer seats (there were about 35, and I'm not overweight, but it was a tight fit). I recommend the lower and middle seats.

We took a day time sleeper bus with HM Happycar from Hoi An to Phong Nha. I received a WhatsApp message from the organizer to ensure we found the bus ok before departing. The bus was extremely clean and in great condition. The little bed capsules were private and lay totally flat, or you could put them into a partially reclined position. I am 5'4" and could lay completely stretched out, my friend is 5'9" and could do the same with flexed feet. There was a USB port, lights and air vents. The driving felt very safe and there were two drivers who traded off which helped us feel safe as well. We stopped 3 times for toilet breaks. After getting dropped off and going about our day, we realized we forgot air buds on the bus. I messaged them via WhatsApp and they responded immediately that they would ask their cleaning staff. They found them and organised a nearby hostel for them to be dropped off at for us to pick up at our convenience. Very impressed overall, would book with them again.

The bus staff is enthusiastic and keeps the customers' dropped items to return them.