Are you going to have two people who can push? If so, I'd take the connectors if you have 2 strollers that you like and that your kids are comfortable in. If necessary, you can add storage bags for the back and cup holders for the pusher before you go. You can buy all of those things near the connectors.
With a double stroller that's front and back, you'll spend a lot of time getting your kids in and out. Plus, if one parent takes each child and you split up for a little while, one will have to go without a stroller. Two single strollers will fold up pretty small. As long as one of you can easily carry both strollers and the other can easily manage both children, I'd go with the 2 strollers.