Cooldown Timers 2 will broadcast cooldown timers.

Sorrens Timers will broadcast skill timers.

An example of the difference:

If I lay down a grounding totem, CDT2 will display the cooldown before I can drop another grounding totem again.

Sorrens Timers will display the duration of the grounding totem itself.

You can find both of them at wowinterface.