The old axiom (pun intended) of bigger is better (all other things being equal) is actually in your favour since live action sports does not seem to be a priority.
Your THX recommended screen size maintaining 40 degree angles from a centered 10' seating is 100 inches (10x12x.84). Therefore, go as big as you can afford.
That said... both brands use slightly different technologies that, unfortunately, each person reacts differently depending on how their brain is wired, especially when it comes to motion (see my post in the other TV recommendation thread).
Ideally, you should try to audition each TV side by side (and not at Best Buy on the show room floor!) but not every retailer will be able to let you view under same conditions (same BD player, same settings, etc). Also, as they are large and a pain to de-install, hard to audition in your home...
Honestly though, from 10', and no light control issues, you won't be unhappy with picture quality from any of the top brands at this price point. The only thing you will regret, believe me, is that you didn't get bigger. I have never met someone who wished they had gone smaller.
For me, the decision was easy as I had a set wall space restriction to play with. Once I factored in the space required for the M22OW's, that left me with 60" of space, perfect for a 65" LG