Bus ride from Kampala to Kigali

Does anyone have suggestions on safe travel from Kampala to Kigali?  Are the buses safe?  Are there some companies that are safer than others?

Hi there
I wd recommend using Jaguar Executive Coaches who I took to Rwanda this July. They were recommended to me by Ugandan friends who have done the journey many times. 30k one way.
Call 0752638699 to book. Some times of day get booked up very quickly.
It's a long journey! I took 3 am coach and arrived in Kigali about midday. Both journeys were without incident :) Have a good trip!