I wanted to purchase a couple of father/son watches and started a thread about it the other day. I was quickly informed of the GW-M5610 as a better option than the one I first had been looking at, and when I checked it out I was sold.
The F91W-1 has a similar square case so the watches look very much alike. I hope that when he looks at his watch he will be excited about knowing the time on his very own watch and be very happy it looks so much like dad's watch as well.
On to the pics! (sorry, crappy phone pics)
A perfectly sync'd pair of Casios!
A very excited seven year old! I have to say it fits him very well.