Theres so many ways you can do secondaries at 39. Haste is great (lower GCD, lower CDs, more crusaders, stacks multiplicativly with enrage, more enrage). Verse is pure damage and some surviveability. Crit is great for bursting through heals to get down into execute range.
The 20% haste/10% verse/10% crit build seems to be pretty popular. If you are fortunate enough to have a jackhammer (or 2), then that provides all the haste you need and you can go full crit/verse.