I need to decide on a rear-facing car seat for my vehicle and I've found both the Roundabout and True Fit Premier on sale... the seat isn't even for my child - I babysit and have to transport a very chunky 14 month-old daily. The baby's parents gave me a safe seat to use but she's pushing the limits on it and they don't have a convertible seat for me. They said they'd keep an eye out for one for me but my fear is that it won't be user-friendly and I'd rather have something I knew was safe and reliable and easy to install and uninstall as I won't be using it extensively. That being said, I know Britax gets raves about ease of install. Is the True Fit Premier just as good? It has a higher weight-limit. Thanks in advance!