I've used Slim Fast before and I agree that it's great if you're on the go. I find the shakes more filling than the bars. I likes the Slim Fast Optima. I think they're less sugar maybe. But it's definitely a quick fix and not something I could stay on for any lengthy amount of time. I couldn't have the same thing for breakfast and lunch everyday... too boring.
Good luck with the wedding! I'm sure it's going to be FABULOUS!