Incorrect, there are duties in Saudi Arabia as well. But usually negligible (~5%).
My understanding is they don't bother applying duties on personal imports, but stamp down with duties when large quantities are imported. My friends regularly import iPads, PCs etc from US for personal use, and never paid any duties.
I have imported a lot of Cisco networking gear, HP servers etc in last 3 years and never paid a dime to Saudi customs, Alhamdullilah. However, I know people how are importing used cars from US/Dubai and paying around 5% mark.