We used the online service to apply for our visas, took less than 30 minutes for two visas. Upon arrival at Windhoek there were long lines at immigration there were probably 20 booths with immigration officers and there were 6 or 8 booths marked for e-visa only, the process was quick and simple, we were out of the airport in about 30 minutes, including firearms permit. Much different than at O R Tambo!