Very good question, both about why we like/dislike caddies and about Bandon. I caddied for a couple years at the Dunes Club, and since then have been lucky enough to play some great courses, including Bandon, with a caddie. I love the experience of playing with a caddie, much more so when it is a good caddie. A good caddie:
-knows the golf course and the game of golf well
-does not have to prove that to you in the first 2 holes
-lets his player set the agenda for whether he gives yardages, reads on the green, etc.
-lets his player decide when they will talk to one another
-is aware of the game being played in your group, but does not make that too obvious
Lots of other characteristics of good caddies, but those are some that come to mind right away, based on experiences with bad caddies. Overall, the caddies at Bandon are very good, and if money is not a big deal, definitely take one.