What infant car seat did you choose & why?

For LO we had the Britax Marathon & we really loved it but we are considering getting rid of it & the 3 (yes 3! lol) bases that we have & replacing it for baby number 2. My main reasons are it is HEAVY & I do not like that it doesn't fit very well into most shopping carts. I love the anti rebound bar but don't know if that alone is worth sticking with it. Advice?