Selfdrive4x4.com provided an itinerary and helped me choose the trip and features that suited me best. They did all the work regarding booking accommodations and keep me informed all along the way. When I encountered minor problems with my vehicle during the trip, the insurance company chosen was responsive and helped resolve the issue quickly. When there was a minor issue with one of my bookings, they booked an alternative location and informed me via text message.
Strengths
I like the shared dropbox folder with files that I could review as they added and updated them. They were very responsive when I wrote questions and asked advice. The standard 22 day itinerary offered a varied and interesting tour of the country.
Improvements or suggestions
I would have liked the option for more discussion before making a choice of itinerary, perhaps with an option of extending the entire trip by spending more time in one location or another. The web site does indicate that this is possible, but when I asked questions about it via email, the person I corresponded with did not pick up on it. In the end, I think the 22 day self-drive tour suited me well, so I am not disappointed, although I might have extended my trip by a few days if we had discussed this possibility more during the booking process.