My personal preference for child seats is a Wee Ride or Yepp or other brand of seat that holds the child between your arms while riding.
Upsides - child is between your arms and you can see them easily. They get a decent view of the road, not the rider's backside. The fitment bar is secure between seatpost and headset, but the seat itself can be removed or moved to another bike. Plus they work on full-suspension bikes as well as rigids and hard tails. The weight distribution is good unlike a rear child seat which makes the back of the bike super-top-heavy. Kid's foot boxes make semi-good front fenders in the wet.
Downsides - they're not cheap. Riding with the seat in place may interfere with your knee movements leading to some knee strike or knees splayed outward. Center-handlebar mounted things are harder to get to (your garmin perhaps?) Your waterbottle is fine but is harder to get to so stop to drink. You can only use them for a few years till the kid is too big.
And the biggest downside? The stoker's not pulling their weight!