The only issue that could really improve this hotel would be a steadier warm water flow; showers alternate between hot and warm. But, one can easily get used to this.
I stayed during one month at the Radisson in Lusaka for business. This is a long time to stay somewhere and not to have any serious complaint; therefore, I will give this hotel 5 points. For a short stay it is rather 4.
Staff is extremely friendly and helpful. There is plenty, and they are always around to facilitate your life. My room was large, well equipped and very well serviced every day. I enjoyed above all the international electrical outlets, which let you connect your equipment without any adapters. Internet was not the speediest, but sufficient to have good communication. There is a pool, a snack bar and a very nice gym for the case you want to work out. Food is ok (after 4 weeks even the most interesting restaurant becomes boring), but above all I enjoyed the diversity at breakfast, of which I did not get tired even after 4 weeks.
Some funny observations to share: a) the hotel resembles a space station out of a sci-fi movie, b) the restaurant sometimes starches napkins so much that they become like sheet rock, and c) as a good corporate citizen one can rent bikes for a deadly ride in Lusaka.