i know i'm going to get flamed by britax groupies for this, but britax also has a reputation for putting positive spins on design shortcomings. for example, the HUGS system wasn't conceived as an innovative safety "enhancement" to stay ahead of the safety curve; it was an afterthought, a patch, designed to allow a seat that otherwise failed the FMVSS213 head excursion test to pass. but their marketing expertise is fantastic, because they have parlayed that into a "britax innovation" and most people believe that it is yet another example of how safe britax seats are.
on the other hand, britax does have several true innovations to their credit, such as the LATCH bar and the versa-tether. those are both examples of superior design.
honestly, the best seats are the ones that fit your child, fit your car, are used correctly every time, and pass relevant testing standards. all seats sold in the US pass FMVSS213 standards, so the only remaining variables are fit to the car, fit to the child, and proper use.