I love my Britax Roundabout! When I had my first child, I did a lot of research before buying anything. I knew I wanted a Britax for the main car seat based on all the positive reviews I read, and my purchase did not disappoint.
The Roundabout is the smallest of the convertible car seats made by Britax. You can use it rear or forward-facing with children 5-40 lbs.
It is super easy to install using either LATCH or seat belts. Best of all, the straps are easy to adjust for the proper fit. I find my biggest complaint about other car seats is that they are hard to install, difficult to adjust, and just do not feel safe for those reasons. I have had nothing to complain about with the Britax!
One of my favorite "bonus" features is that there is velcro on the sides to hold the straps out unti you put your child in again. It sounds silly but it really is helpful that I don't have to mess with getting the straps out of the way each time I place my child in the car seat.
I wouldn't use any other brand as my main car seat!