Britax is consistently one of the top rated car seat brands. I bought the Marathon for my little one because of the good reviews and it was reasonably priced for the features it offers. (Retails for $300).
Easy to install, plush materials and easy to adjust the seat belts as your little one grows. Rated for 5 lbs and up, so I started using this from birth onwards in one of our cars as opposed to using an infant seat. There is an infant positioner that comes with the seat that you use until your little one hits 3 months. My only small complaint is the tethering that the manufacturer recommends you use even when rear-facing. Not all cars have floor tethers, so it can be difficult to maneuver your little one around the tethers in that position. It's not an issue when the seat is installed in the front facing position.
This is quite a wide seat so you should make sure it works for your car. It's best for those with one child IMHO. If you have multiple kids that require car seats, I would probably go with a narrower seat.
This car seat is great! You get what you pay for with car seats for sure. We have one of the cheaper ones as well and you can definitely see the difference. The straps are so easy to adjust in height and are also so easy to tighten. The cheaper version requires you to pull with all your might, the Britax slides super easily. I have nothing negative to say about this seat. Love it!
These reviews are the subjective opinions of ChickAdvisor members and not of ChickAdvisor Inc.