After growing for avocados for more than 20 years, I've learned a lot about different varieties and their characteristics. After years of observation through avocado taste trials (it's tough work but someone's got to do it...) I've come to the conclusion that there are substantial differences in fruit variety and quality during the course of the season for each variety. The industry standard, hass, is truly an excellent piece of fruit during it's season. It holds on the tree for up to eight months while maintaining quality. When the typical hass season begins in December, the fruit has a lower oil quantity and as the season progresses so does the oil quantity. I generally prefer to be finished with harvesting hass in June due to the decreased shelf life as the oil quantity increases.
Luckily there are three other excellent varieties ready for harvest at this point. Lamb hass is a larger piece of fruit with darker skin and excellent flavor. Retailers will often substitute this piece of fruit for regular hass without any notice. Reed's are also available starting mid-June. This is a much larger, more spherical piece of fruit that features a nuttier taste and creamier texture. It really is a superb avocado.
Finally, the winter varieties are also grower favorites. Both Bacon and Fuerte avocados extend the season for the late Fall and Wiinter months. Fuerte in particular has a rich, unique flavor. It is a real treat to have these two varieties to keep us in stock of fresh avocados even in the middle of winter.
The point that I labor towards is that each avocado variety is excellent when harvested at its prime - meaning when it's oil content is at optimum. Too little oil content leaves the flavor weak and fruit a bit watery while too much oil content shortens the ripe window and makes fruit difficult to handle. The seasons of these varieties can overlap, but hopefully this will help avocado lovers learn about the benefit of growing and offering multiple varieties to the avocado eaters of the world!