So, we booked the tour one day in advance through getyourguide.com in order to get a reliable tour operator like many people suggested.
We could book our pickup for 3, 4 or 6 pm - we chose 4 pm. The meeting point was the gas station at the road between merzouga and erg chebbi.
We were there at 3:45 pm but until 5:45 nobody showed up. We texted our contact at the agency, she didn't reply and didn't pick up her phone. Eventually - after 1:15h of waiting and trying to call her - we could reach her and she promised to check what happened and give us a call back. Again, nothing happened until we called again ourselves. She told us that the people supposed to pick us up were stuck in traffic?!?!( Which traffic? In the desert?) . Well, they finally came and picked us up - well they didn't pick us up, but we had to drive with our own car and a guy hopped into our car to show us the way (there was not really a road, it was off-road and our little fiat panda did very well next to all the jeeps;-))
When we finally arrived at the camel ride starting point, we insisted on going directly on the camel's to see the sunset, as time was getting short. The camel ride was like 10 minutes to the dunes, then we could take pictures and play around in the dunes, before our camel guide tried to sell us some cheap souvenirs. Really?! Then the ride to the camp started, it went around the starting point and ended behind all these places ( approx. a 20 minutes ride crossing the camel starting points and "road" - nothing spectacular to see). So, we were not in the desert but just next to it. Two other camps were directly next to ours, so there was no feeling of solitude at all! The guy at the camp explained that the marrocan government expelled all Sahara camps due to environmental issues. That's sad but understandable. What I don't understand is why they don't tell us in the description of the tour!
So we've spent the night in the "desert", in the next morning we were told to go to a a mini dune right in front of the camp to watch the sunrise. We've asked the guide where the sandboarding takes place, and he told us that there are boards lying at the entrance of the camp that we can grab, but the boards were not really usable and the dunes not high enough. So, sandboarding was not really an option.
The next day, the owner of the camp came and apologized for the delay in picking us up. After a discussion and my suggestion to get a discount from the tour operator he wanted to give us 100 dirham back out of his own pocket, such that I do not write anything negative. Well, I didn't take it, as it felt like a bribe. He was really afraid to get in trouble with his boss. So, the apology was more because of his fear of getting a bad review on TripAdvisor than being really sorry about our inconvenience. He told us that somebody in his family had died and that was the reason for the delay. No idea whether that's true or not. At least it doesn‘t sound like a traffic jam. Still, no excuse to let us sit there without any notification.
Btw: our entertainer in the camp told us that the camel rides only start at 6 pm, never at 4 pm...
So, is the trip worth the money: not from my side. You can do everything on your own. Playing in the dunes since they are accessible by a fiat panda, and there are camps you can book directly over booking.com if you're interested in sleeping close to the desert. And the camels are happy if they don't have to carry the tourists everyday.
We did our walk to the highest dune on our own the next morning and it was really awesome! And to leave something good: Mubarak, the guy in the camp, was a real funny guy, and the breakfast was one of the best on our trip so far.