I've read long tirades about the open tour buses but generally I found this a good way to get around with a few provisos. First of all we were promised "We garanteed all buses are A/C, brandnew with more leggsroom". They're not, they don't and they haven't. However they all left around the time they were meant to and arrived where they were meant to nearly on schedule.
I didn't get any pictures of the first bus we were one which was a pity because it was half sleeping bus, half sitting. I snagged a horizontal seat once we'd spent an hour tootling around Backpacker District picking up stray passengers and snoozed most of the way to Mui Ne only fully waking up when our driver got particularly enthusiastic with the brakes.
On arrival the tour buses operators will try to sell you a room in one of their hotels or trips during your stay but you're not held captive, there are options.
- Pre book your hotel (or say you have) and after a while the bus will take you to the door of your accommodation
- Have a look at what they have to offer, it might not be so bad after all
- Jump a Xe Om, get a Taxi or walk to where you're going
We chose option 1 and had a cold beer in their affiliated cafe for half an hour and watched the world do very little indeed
We confirmed our travel the day before we left and our next trip to Dalat was in a less attractive bus without air conditioning unless you count open windows.
On the HCMC to Mui Ne route there was a stop at a petrol station to pee and buy fruit and snacks, there aren't any such facilities on the way to Dalat but they did manage a scenic stop to cool the bus and stretch your legs on the way.
Look carefully, you should be able to see the extra brake. The scenery was outstanding on the way and made up for the bus being a bit on the rough side. When we arrived we opted for a taxi the quicker to get a shower and wash the dust off.
The Dalat Mui Ne run was in a little Mercedes Ben - not a typo.
Which was comfortable and well driven and, after essential repairs, got us into Nha Trang in three hours.
So Open Buses, not a bad way of getting around, I'd happily use them again, just remember it isn't always exactly what it says on the tin.