For my taste, the best format for an action match is the way Kaci and Pagulayan gambled. Best three out of five races to 21. Plenty of pool, and no matter how things proceed, each player tends to be in with a chance to win the match until the end, which is what makes it watchable.
Three out of five races to 21 is still a marathon of the highest order, but there is far less danger that the match will turn into a snooze-fest, as so many of these long races do.
To each his own.