Britax Roundabout or Marathon?

I have the roundabout for my son and he loves it. I just purchased a diplomat for my younger son and it is great as well. I actually like the diplomat more so will change my older son's roundabout to the diplomat, but keep in mind these seats only go up to 40lbs. My sons are on the small side so they will last us a while.

We have both and LOVE both. My oldest daughter (3 1/2) has always been my "bigger baby" (95th% for weight & height)...we put her in the Marathon at 8 1/2 months old...and she's still in it at 3 1/2 years old, with still lots of room for her to use for a long time to come. My youngest daughter (21 months) is our "small baby" (10th% for weight & height) is in the Roundabout...with still lots of room for her to grow. SO....although I LOVE both carseats, based on my experience with my oldest daughter being (like your daughter) "big for her age" (she weighed 26lbs. at 1 year), I would go with the Marathon, if I were you. A little bit more $ than the Roundabout, but you will get a lot longer use out of it with her being a tall/big girl....and it will hold her until she is ready for a booster. Again my daughter is 3 1/2 and I have no intentions on moving her out of the Marathon until she reaches the max. weight limit for it...due to safety reasons and the 5 point harness being safer than the booster seats.
Hope this helps. Godd Luck!

FYI, Britax makes these carseats under the Fisher Price brand name for a much lower price. The Fisher Price Safe Voyage is the Marathon but with a Fisher Price label and different cover. http://www.albeebaby.com/fiprsavodeco1.html

The Roundabout is pretty small and won't last that long if you have a taller/heavier child. We have this seat, which is fine because my children are both in the 10th percentile for weight, but I did have to move my oldest into a bigger seat this year because she's tall and outgrew the Roundabout height-wise.

Hi C.,

We had the same dilemma and decided to go with the Marathon as it will last longer for a little more money :) We are very very pleased with it!
Our little one is on the tall side, and we transferred him into the Marathon from his infant car seat at 13 months,and now at 18months old, he still has plenty of room to grow into it!
A.

Go with the Marathon. I have both and love both, but if your daughter is on the tall side she will outgrow the Roundabout too soon for the booster. My second daughter just outgrew the Roundabout at three (she is VERY small) and is now using the Marathon.