I have a list in my iPad that I add to whenever I hear good things about a specific variety from multiple sources . I also ask or refer to posts from the Gurus that live in my climate like Adriano , Herman , Nelson , Paully , Chivas .. Etc .
Also anything recommended by Pierre Baud for cold climates .
On the experimental side I have family in Greece and if they have a variety that is awesome , especially from a high elevation mountain village , then I give those a try .
Also there are many locals you get to know who have been growing a tree for years who don't know the variety ( and don't care ) that is great .
I thin out the herd as needed , if a tree is sickly ( both paradiso neros ) , or just not up to par they get scrapped . I don't sell them or even give them away anymore , I don't want to perpetuate a crappy variety making the rounds wasting people's time .