Biking with Baby

I don't even own a bike yet, but I am already shopping for baby seats. I can't go riding without Quinn, so I have to consider having him in tow before buying a bike myself. I am considering the iBert, Topeak's BabySeat, and the type my sister has WeeRide Kangaroo. All three are mounted differently. The iBert is mounted essentially to the handlebar. From what I can tell (see and read), it will turn when you turn the handlebar. The web site has a video you can watch. What I like about it is the height, Quinn could see really well. The BabySeat by Topeak is a rear-mounted seat. Again, from what I have read, there is complaints of the rear-mounted seats making your bike harder to balance. I don't know that I like the thought of Quinn behind me where I can't see him. Lastly, the Kangaroo has my favorite mount. It mounts to the center bar of your bike, therefore, it will not turn with you as the iBert does. Some complaints of this mount, though, is that your knees hit the carrier while pedaling. I am not tall, short actually, and I don't know that this will be a problem for me. What I do not like is the height of the seat (it sits low) and the padded thing-y that seems to impeed the view for the child. I wonder if it is a mandatory part of installation. Why is it there anyway? If the child is secure in the harness, I wouldn't think you would need to protect them from the handlebars. Crazy. Makes me wonder if Michael could BUILD me something... lol.