It's also worth mentioning that if you dual wield, and put the enchant on both weapons, the +strength buff stacks. So if it procs once from your main hand, and then 12 seconds later procs from the offhand, you will get a +200 strength buff for 15 seconds at that point. Yes, the offhand will refresh the timer for the combined buff.
In other words, crusader (x2) is WAY better than crusader (x1). When one considers that the proc is meant to go off twice per minute, per hand, you can have them both stacked up quite frequently.