The review below is the personal opinion of Daniel K. and not that of SafariBookings.
Dunas Safari: avoid!
Namibia is a magnificent country. The lodges are generally well located, often with spectacular views, and offer every comfort. What we ask of a tour operator, and what we pay them for, is to offer an interesting programme, without too much stress (we're on holiday, after all) and, above all, a realistic programme that can be kept.
The organisation of our trip by Dunas Safari did not live up to our basic expectations. In particular, several transfers during the 3rd week (when we no longer had a hire car) were not properly planned and this meant that on several occasions we missed activities that had been included in the programme and paid for! Another couple we met during our trip, who had also used the services of Dunas Safari, experienced similar, if not more unfortunate, problems.
In comparison, Dunas Safari turned out to be much more expensive than other operators and we had the unpleasant impression that we were paying a surcharge because we were Swiss....
Apart from that, Namibia is a beautiful country, often breathtaking, which we highly recommend you visit; you'll find other excellent tour operators in Windhoek.