I switched around 8 months. We first went to a graco comfortsport, which was the only convertible that could fit rear facing in my tiny car. I'll admit I was very frustrated when DD outgrew the rear facing harness by 14 months then outgrew the entire thing by 17-18 months, although DD is very tall so I know that was part of the problem. We now have a sunshine kids radian 65 which I love, although I don't think it could fit rear facing because it's pretty tall. If space isn't an issue you'll have a lot more options. Many people I know are very happy with britax carseats, but they're very large.
We switched around nine months but kept her rear facing til she was about 18 months old. We have the britax marathon too and love it. It's easy to install too!
We switched at 7 months with both boys. ?They're both now using Britax Boulevards. ?Pretty much the same as the Marathon, with a little extra padding for babies, and they have the side impact protection on either side of the head. ?I also think they're easier to adjust the height, since you just turn a knob rather than re-thread the strap through a new slot.
With my girls, they lasted longer in the infant seat, but with the boys, I switched them out at around 8 or 9 months when it got to be more of a burden to carry them in the infant seat to the car, than to just put them in the convertible. I can usually tell when I'm ready because I start taking them out of the seat in the car instead of bringing the whole thing in. I have a Britax Roundabout which I absolutely love that they moved into.
Re: when did you switch from infanct car seat...
4 months for both of them- they hated the baby bucket.
I have 2 Evenflo Triumph Advance seats.
DS - December 2006
DD - December 2008
We switched around nine months but kept her rear facing til she was about 18 months old. We have the britax marathon too and love it. It's easy to install too!
At around 6 months. He was 19 lbs, and could sit very easily by himself at that point.
We did a graco seat, not sure what it was. Then we found a britax on sale, around 9 months, and bought that as well. So we had 2, it made it easier.