Using PWR, it's possible that at the end of the season, in a conference tournament, a loss would help a team more than a win if that loss results in that team's opponent becoming a TUC. Using KRACH, though, a win will always help a team and a loss will always hurt a team. Point for KRACH.
Also, using KRACH, if a team played the top 5 teams in the country every game for an entire season and went .500, they would finish no worse than 6th. If they played the bottom 5 teams every game and went .500, they'd finish no better than 53rd. Using, PWR, though, neither of those are guaranteed. Another point for KRACH.