I would skip the roundabout too. GO for the Marathon.. Here are the differences between the 2.. you will get more use out of Marathon. That is what I did skipped Roundabout and went straight to Marathon. We have Regents now but still have Marathon as extra seat and for traveling.. My DD is 4.5 yo, 40 lbs and 42 inches tall and still fits in Marathon.
Info directly from Britax website:
www.britaxusa.com
ROUNDABOUT:
Rear Facing 5 lbs. - 35 lbs. up to 40'' sitted shoulder height 10.5'' - 15''
Forward Facing 20 lbs. - 40 lbs. up to 40" sitted shoulder height 12'' - 15''
MARATHON:
Rear Facing 5 lbs. - 35 lbs. up to 49'' sitted shoulder height 9.5'' - 16''
Forward Facing 20 lbs. - 65 lbs. up to 49" sitted shoudler height 12'' - 16''
My girlfriend has a Marathon for DD1 and Boulevard for DD2.. She doesn't like Boulevard at all and wishes she would have got Marathon for DD2 as well.
Kelle
Mom to Riley (05-03)
(She's a girl, not a boy)
Used to sit in REGENT
NOW SITS IN FRONTIER
WE LOVE!!!