EVeryone else has gone over the standards part really well already, so I'm not really going to go into that. What I'll do, is relate my experience.
We started out with an AO for dd when she outgrew her bucket seat. I had wanted a MA even then, but couldn't justify spending $349 for it (this was before the price drop in CAnada.)
When I was pregnant with ds I knew that the 2nd convertible to buy would be the MA. The price dropped to $299 and I bought one, and immediately used it for dd since I figured no sense in having a nice seat in the house and an AO in use.
When I first used and installed the MA, I was blown away. It does have a lot of features other seats didn't at the time, and installed so much easier than the AO. This was back in 06 though... new seats have become available since then, mainly the Radian and EFTA here in Canada.
I have both, and have used all 3. Prior to the arrival of the EFTA, I always recommended the MA first (length of use, ease of use) and the Radian 2nd (length of use, but sometimes difficult to install.) Now my top 3 chocies are EFTA, then MA, then Radian. Reason being that I don't see a huge difference between my MA and the EFTA, and I don't think the MA is worth double the price of my EFTA. Both install well in my vehicle, the EFTA fits ds with more room than the MA as well, which is another plus for it.
The MA remains #2 for ease of installation and extended length of use, but I don't think Britax is alone in the top of the field anymore.
ALL companies do ongoing crash tests on their seats. How often they repeat crash tests varies from company to company, but they all do it. The reason they repeat crash tests is because in the event a defect is found, they need to know the last time they did a crash test that that defect wasn't present. It saves them money and gives a more specific recall period. They also need to be able to continually know that the seat meets standards.
Regardless of which manufacturer you decide on, the best seat is going to be one that fits your child, fits your vehicle, and is used correctly every time. They all pass the same minimum standards, and all manufacturers do ongoing crash tests. Most seats are coming with either EPP or EPS foam now, which is about the only thing I truly consider important when speculating from a safety standpoint...
One other thing to throw into the mix - the primary protection to the child will come from the vehicle itself. The carseat is designed to allow the child to have ride down time while the vehicle absorbs some of the crash forces, and then it distributes the forces along the entire body of the child instead of just chest & pelvis. Rf'ing seats cradle the neck and head as well, which is another important aspect.... but anyways, my point being that pretty much any carseat that is installed and used properly, and is the appropriate seat for the age and weight of the child, is going to perform the same job and will protect the child. Some manufacturers are more vocal about sharing their "successes" from kids who were protected by their seats in a crash. But that doesn't mean that the child wouldn't have been as equally protected in another seat. :thumbsup:
At one time I think Britax could've clearly been called cream of the crop, just because they had a lot of features that other manufacturers have now incorporated. They are safe seats, but not necessarily safer than any others, and aren't alone in the ease of installation category anymore, so I certainly don't fall into the camp of "only ever consider a Britax."
Are they safe? Yes. Safest? Impossible to say. And I'd say the same about any other seat you asked me about - that it's safe, but no way to know if it's safest. Carseats when installed and used correctly to a very good job of protecting kids in crashes regardless of what brand you buy. So choose one based on fit, ease of use, and right stage of travel for your child - and if you have other personal factors like budget, or needing to buy from a specific store because of gift cards or whatever, throw those into the mix too. :thumbsup: