Spring is right around the corner and that means we are going to be busting out our bicycles. I love to ride with my son and after looking at a lot of brands and tons of other reviews I chose the Topeak Baby Seat II for us to use. There are a lot of reasons for this choice, but the main is safety. The Topeak Baby Seat II is a little higher in the back and a little wider on the sides, so god forbid I crash it should provide more protection than the others. Also, the seat isn't hard mounted onto the bike frame; it's mounted on a rear rack and has quick releases. This allows you to take on and pull off the seat in less then 15 seconds so you don't have to dedicate a bike for riding with your kid, ride around with a baby seat when your child isn't with you, or spend 10 minutes putting it on and taking it off using tools. Another thing I liked, and haven't gotten up to yet, is the weight limit… 48 lbs!! By the time they hit 48 lbs they should be riding their own bike and you should have kid 2 on yours.
There's only 2 downsides I have found thus far, first, it's not designed for 29ers, and second, depending on how close it mounts to your rear seat the foot rests could smack your heels when you pedal (I had this on one bike but not the other 2 I tried).
In addition, the rack can be used for other bags or storage when the seat isn't being used, like the MTX trunk bag (that I love) or the trolley tote collapsible basket (that I want to buy) which is great if you're running to the farmer's market or commuting to work.
Check it out on amazon here: Topeak Baby Rack II w/ Disc Rack