We travelled in November, 2012. Tour operator was Randa Rady (+2 0122 27 20 224). I would highly recommend them.
We had 3 nights on a Dahabeya, with only my husband and I, and another adult family of three. It was very serene every morning, waking up to sunrise, then docking at ports and seeing different sites. We would then board the ship and have the two meals onboard, sail to the next destination. I felt so lucky that we didn't choose some of those bigger cruise ships which are mostly empty, whereas we had a small little Dahabeya, with very personal experience, got to know our fellow travellers. The decor and interior were 4* and the staff were all very helpful. Our guide Abdul was excellent, he really put in every effort to make our trip special. He gave me extra Egyptology lessons on the sites we visited, I knew the family tree of the gods and goddess off by heart by the end of the trip. We also added extra stops and sites to see, without having to increase the price of our trip. I was totally touched.
The sunset is not to be missed, it was beautiful and the sky changed colours every few minutes. Make sure your camera has a video function.