Personally, I'd rather get a seat that is really fantastically safe and just wash the cover and then let it all air out for a while. I have a Britax Marathon in my car, my mom has a Graco in hers. DD LOVES riding in her Britax--she is just so happy and comfortable. Plus, that thing is rock solid in my car--you would think it was part of the actual car--it doesn't move or shift even a millimeter. My mom's Graco make DD miserable--she complains about how uncomfortable she is and the seat shifts all over the car. Its just not safe. I love the Marathon too because DD can stay in it until 65 pounds, and I personally believe in keeping them in a 5-point harness for as long as possible.
I never had the Companion--Britax developed their infant seat after DD was born. I will reuse her Peg Perego infant seat for this baby entirely for financial reasons, but if I was starting all over I would buy the Companion just based on Britax's reputation for safety alone. Plus, the height and weight limit is higher on the Companion, so the baby can stay in it a lot longer. DD outgrew her Peg when she was 5 months old, which was rough!
I never had the Companion--Britax developed their infant seat after DD was born. I will reuse her Peg Perego infant seat for this baby entirely for financial reasons, but if I was starting all over I would buy the Companion just based on Britax's reputation for safety alone. Plus, the height and weight limit is higher on the Companion, so the baby can stay in it a lot longer. DD outgrew her Peg when she was 5 months old, which was rough!