We bought a Cosco Scenera for our trip to Maui (still here). It's awesome. Very light, and it comes in a plastic bag with a carrying handle (unlike most seats which come in a big cardboard box). Very travel friendly.

Kids are used to sitting for longer periods of time (and falling asleep) in car seats. You've got a much better chance of long periods of peace with the kid in a car seat than with the CARES harness.

We watched all the other parents bringing along Britax Marathons and struggling due to the weight. While the Scenera isn't perfect, as a travel seat, it gets two big thumbs up from me.