Having Mr. Xiao walk us through the process of growing guava trees, we made a form to introduce the fruit by cultivar types, appearances, smells, tastes and sweetness:

Cultivar types	Pearl Guava	Taiwanese Psidium Guajava	Fragrant Guava
Pictures
Cultivation characteristics	It has good resistance to disease and therefore easy to cultivate. The quality is better and more stable after October. It is better to avoid harvesting in summer and hot weather.	Originally from tropical America, the red-fleshed guavas have been introduced to Taiwan for more than 200 years. It has good resistance to disease.	Compared with Taiwanese Psidium Guajiava and Pearl Guava, Fragrant Guava is less disease-resistant, therefore it is less easy to cultivate.
Appearance (color, shape, and touch)	It is emerald green in color, oval in shape, rough in touch.	Dark green in color, smooth in tough and small in size, the fruit is white gourd shaped and its pulp and seeds are hard.	Greenish yellow in color and round in shape, the fruit is a little bit rough in touch but overall, it is smooth.
Smell	Slightly sweet	Musky	Very sweet with strong guava fragrance
Taste (soft, hard, crispy)	With higher level of sweetness, the flesh is thicker and more delicate in autumn and winter seasons. In summer, when the weather is hot, the flesh is not that crispy and the fruit softens easily.	The fruit is hard and crispy but not easy to chew, for there are too many seeds.	Fragrant Guava is easy to bite, more tender and chewable than the other two. It is popular among kids and elders with soft fibers.
Sweetness	Sweet	A little bit harsh	The sweetest

　　Because of this visit, we got free pearl guavas picked in Mr. Xiao’s orchard. We were so happy about that. The sweet fragrance of the guavas encouraged us to have another bite. Each type of guava has its uniqueness and followers. Though Taiwanese Psidium Guajava tastes harsh, it has strong musky smell and fragrance. And many people just love that. After tasting these three kinds of guava, most of us thought that pearl guava was more crispy and tasty; fragrant guava was very sweet and fine, and we could smell it at a distance. We also had some psidium guajavas taken from the school’s Guava Festival. Though they were not that smooth and sweet, the strong fragrance came out suddenly after one bite. They tasted good as well. Thanks to the technology, there are a lot of cultivar types of guava, such as Pearl Guava, Fragrant Guava, Taiwan Psidium Guajava, Juicy Guava, Emperor Guava, Red-Flesh Guava, Water-Melon Guava, Crystal Guava and Papaya Guava. If there is a chance, we would like to taste all of them!

Source: Guava Family; Council of Agriculture, Executive Yuan. http://kmweb.coa.gov.tw/subject/mp.asp?mp=121