H.,
Safety is important - everyone can agree to that. I have twin boys and so we have to buy two of everything, and in this case, FOUR (2 for each car).
I did a TON of research before getting our convertible car seats. My DH is very tall and my twins are tall for their age. So I wanted to take that into consideration as well. I also took into consideration that we do sometimes travel by airplane, so would be taking the car seats with us to use on the plane.
Try and make up a list of things like what I just mentioned above. While all car seats have to meet specific safety standards, certain car seats are easier to install than others, and some work better than others in specific car models. Lastly, some are better than others for taller children, go up to higher weights/heights (so you can use them longer), and are more plush, easier to clean, etc. etc.
I used Consumer Reports web site. The Graco Comfort Sport was rated second to the Britax car seat, only by one or 2 points when I was researching this, and it wasn't due to safety issues. Being that the Graco Comfort sport is less expensive than Britax (and I just couldn't afford to spend over $400 for only 2 car seats, then another $400+ for 2 more so over $800 total even after a discount and a coupon), and I learned that it fit better in airline seats than the Britax (and is also a little lighter weight for carrying it through the airport I might add), I purchased 2 of Graco Comfort Sports at BRU.
A friend of mine with twins gave me her 2 Britax car seats (for free and they are in mint condition & accident free!) and we put those in our other mini van that DH drives. They are bigger, bulkier, just as frustrating to install with the tether, just as frustrating to adjust the harnesses for when your child grows, have a little thicker of a cushion on the seat, and are a little bit heavier. I honestly can't say that I think one is truly better over the other.
Besides Consumer Reports, I also reviewed the Baby Bargains web site. Do a google search on Baby Bargains -- the site is through Windsor Peak Press and the book is by Denise and Alan Fields. The Forum on there is helpful too.
There was another site that I had found to be helpful too, especially if you have a car/vehicle that is a couple of years old. Car Seat Data (www.carseatdata.org) lets you search by vehicle and tells you how well particular car seat models fit in your vehicle model based on what people have submitted in to the site with that car and car seat model.
Our older mini-van has an integrated car seat. We had it for my oldest when he was young. Personally, those are MUCH better than any car seat I've found on the market and easier to use. If you drive a mini-van or an SVU that has seats that can be taken out, I would seriously consider cruising eBay or contacting an auto parts dealer to see if you can purchase just that seat with an integrated car seat and getting it installed. It may cost you a bit more $$, but if you plan to keep the car and have more kids, it will be worth it. If not, consider leasing a car with integrated seats in it the next time you lease (that is, if you lease).
Also, if you shop at BRU, if you are buying two of the EXACT same item, you can get a 10% discount. So if you buy 2 of the exact same car seat you get 10% off the total cost of both. This is only good in store and you may have to ask a Manager so the cashier rings it up correctly. However, they will not give you the discount (usually they won't) AND the $10 off coupon that they have in the BRU sales fliers that you get in the mail etc. So you have to figure out which way saves you more money. On a $200 car seat, you will save $20 vs. only the $10 coupon.
Good Luck!
--K.
Mom to Alex (11), Aaron & Aidan (2)