Re: Roundabout vs Marathon
The Roundabout 55 has the same shell as the new Marathons. The only difference is that the Marathon has a no rethread harness adjuster and a slightly heigher top harness slot height. It also has small head wings. I typically see Roundabouts being sold with the Oynx fabric, which is a slicker fabric, a little like a windbreaker maybe? There are more choices of fabric with Marathons, and more plush options. It is likely that the plush options would feel more expensive next to the Oynx, but Marathons are available in Oynx as well.
The Roundabout55 is a great seat. If the no rethread harness adjuster and higher harness slot height is important, go for the Marathon. If those options are not important to you, than the Roundabout is a great choice. Again, both seats have the same shell, and have a number of overlapping fabric choices.
Cristina, Mama to Michael 03-16-06 , Nathan 01-16-11, and an angel 01-20-09
Go with your gut, follow your heart.