I found X-tended Range patterned the best out of my Ithaca 12ga.
However, I bought shells manufactured in 2005 and 2006. I had some quality control issues with the sheels in 2005, and after last season shipped them the hulls. Winchester did some ballistics comparison, and without a live round, were unable to find anything conclusively wrong.
However, just for my concerns, they sent me a $20 Winchester Cash card, good towards any Winchester products. By far, that's the best customer service I've ever experienced from a firearms manufacturer. I do believe there was something funky about that lot of shells, but they're gone now, and the current batch of X-tendeds I have are deadly out past 50 yards...
I'm not sure about Hevi-shot, but Winchester stands behind their load, and will do anything they can to investigate any concerns you may have
PS> I have heard from several friends, and it seems that X-tended Range always seem to pattern better. However, I believe that the Hevi-13 #4 seem to take more birds, and have slightly more energy in the load...