The coffee grown on the East side of the country -- particularly the Bugisu region -- has the best reputation. However, coffee grown on the Western side of the country in the Rwenzori mountains is increasingly improving year after year. (Bukonzo is one of the better established co-ops on the West). Uganda also grows a significant amount of robusta all over the country (their robusta is often referred to as "drugar")
It is a versatile coffee that is best anywhere from 10 seconds into the 2nd cracks all the way up to a rip-roaring 60 seconds. One of the most forgiving beans to roast -- it can be enjoyed at a wide variety of roast levels.
Uganda is the odd-man out of the African coffees. Their washed-processed bean ends up tasting much more like a premium Sumatra as opposed to tasting like an African coffee. When Indonesia has a poor harvest, a lot of roasters substitute partial blends of Uganda to stretch out their supply of Indonesian coffee. The other regions grow quite a bit of robusta, but even the ones growing arabica do not yet reach "specialty coffee" quality, and the arabica offerings are sold as "a robusta substitute"