The coffee at Jiko is Kenya AA bean - likely sourced from Joffrey's. Kenya's bean is robust, deep flavor, not fruity, very complex with hints of floral...usually roasted dark. I really like Kenyan and Tanzanian coffee beans for evenings as I like the stronger, bolder tastes. For breakfast, I generally prefer the more tropical beans, especially Hawaiian Kona and Jamaican Blue Mountain. Both are generally medium roasted, fruity notes, sweeter beans. Middle-of-the-road coffee is usually the Columbian, Brazilian, and Central American beans which all have a similar nutty, semi-strong flavor depending on how they're roasted. SE Asian beans like those from Indonesia are often similar too, with just a hint more tropical - but rather than fruity tones, they tend more towards coconut tones.
Jiko is one of the few places in Disney where I really like their coffee and get it after a meal. Most of the rest of Disney's coffee isn't BAD, but just isn't anything special. A vast majority of the coffee I drink at Disney is the stuff I bring with me - whole beans and a grinder to make my own in the villa. I generally bring two coffees - one breakfast bean and one evening bean. I'll be up there next week, and intend to bring Jamaican Blue Mountain beans for mornings, and a medium roast Ethiopian Yirgacheffe bean for evenings.