Cleric/Ranger Multiclass or Ranger-->Cleric Dual Class? (BGIIEE playthrough only)

I've been hearing about this cleric/ranger build for a long time, and I'm very eager to try it out. I'm not certain, however, which way to go.

Can anyone help a brother out with some advice? What are the trade-offs and advantages of one method over the other?

Also, if I do the dual class option what level should I go from Ranger-->Cleric

ONLY THE SECOND GAME! :)