What are your recommendations for sweet seedless mandarins? Preferably with fairly high production.
Satsuma, Kishu, Shasta Gold, Page (has a similar sort of flavor to Minneola tangelo, although I slightly would prefer just eating a Minneola tangelo more than it), Dekopon (also known as "Shiranui" or "Sumo", very sweet and very rich, almost slight mango flavor), in that approximate order.
Lee x Nova is also not a bad mandarin, if you prefer the more "conventional" mandarin type of flavor.
You need to research all these varieties before you buy, because they all of their own sort of unique peculiar advantages and disadvantages, too complicated to get into here.
Xie Shan is just a sub variety of Satsuma. I am guessing it probably doesn't taste very different, although it might be slightly more sour and flavorful. Satsuma trees can take many years until the fruits coming from the tree develop maximum flavor, and the flavor can be very dependent on the growing conditions. Too many people taste a Satsuma fruit from their 2 or 3 year old tree and then (wrongly) decide that Satsuma does not really have much flavor. But in my opinion, the very best mandarins I've ever tasted came from very mature old Satsuma trees, the fruits freshly picked from the tree. The fruits start tasting worse after approximately 3 days after being picked from the tree. So this variety also seems to have a shorter shelf life than other mandarins.
Lisbon lemon is my favorite tasting of all the common variety lemons, it is the most standard lemon found in a supermarket. Ponderosa lemons are very ornamental and noticeable for their very large fruit size, a prolific fruiting of the tree, though the flavor is just a little subpar.