I love the Boulevard Britax carseat.  It may be mor expensive than others, but it is worth every penny.  I love all the safety features, and that the manual fits in the carseat so I never have to search for it.  I also love how comfortable it is for my kids.  We traveled from California to North Carolina....the pacific to the atlantic...41 hours in the car, and my kids were comfy the whole time.  They slept great and never whined about wanting to get out.  I recommend the car seat to everybody I know!