I have tried many pellets, hand weighed and shot in a perfect indoor environment. My gun has a Vortek sub 12 ft lb kit in it. The JSB Exact 8.44 are the by far front runner unless you want to pay the price for the JSB Premier, and frankly, there is not that much difference.
I will tell you that what they say about break-in time is true. After now more than a year and thousands of rounds, my TX has turned into a real tack driver, performing better the more it gets shot. Out to 50 yards, while not apt of energy compared to my pcp’s, it is deadly accurate.
FYI, it also shoots the JSB10.34 and the Crosman Premier’s well. Mine does not like the H & N pellets at all.