When it comes to produce there is so much variety out there. But you will miss out on most of that if you keep your shopping strictly to the grocery store. Farmer’s markets offer varieties that you will never find on stores shelves. That is especially true with avocados. Now I live in a state where you will never find an avocado tree. So our only option is the grocery store. In the grocery store in Michigan, you only find Haas avocados. This variety has become the standard. Typically when a certain variety of produce has become the standard in the supermarket, it usually has nothing to do with the taste. Grocery stores are looking for long shelf life and cheap prices. The Haas avocado ships better than the other varieties, hence that is what you find everywhere. 
This is why when I had a chance to visit a farmer’s market in Laguna Hills, CA in February I wanted to see what they had in the way of varieties. I found a vendor selling the Fuerte variety. This avocado has a more pear like shape. It is also known for it’s nutty taste. Unlike the Haas, the Fuerte does not turn darker as it ripens. It remains a green color, so don’t go by the color only to judge when it’s ready.
Availability: Harvest late fall through spring.
Final Thoughts: If you can get your hands on this variety, do so. My wife said it made the best guacamole she has ever had!