Both places are nice and I have stayed at both. I personally would choose Banyan Bay over Robert's Grove. Just my opinion. But Banyan Bay is all 2 bedroom units so perhaps there are better choices on AC for a honeymoon. While RC is on the mainland technically, it is not really much closer for inland mainland trips as you have a 45 minute unpaved road on & off the peninsula each time. Maybe you shoud consider splitting the trip up and staying part on the mainland, truly inland, and then part on either beach. For laying on the beach, AC is better as she will get eaten alive with sand fleas in Placencia! Swimming/snorkeling great at either place (closer to the reef from AC but good snorkeling off Placencia as well). Way more choice of restaurants in AC if you are into that. Placencia is cheaper overall for diving, eating, etc. Just some thoughts on each place...