In comparison (if there is one) to the 360's, the ICON will be most similar. ICON is a fantastic shoe and the best that I have had the pleasure of owning. No break in period, light weight, stylish and VERY comfortable for walking 18 or 36 in.
Now, the FJ Sport is also very comfortable and a great product. It is a easier on the pocket book but you are not giving up any comfort or style points. The shoe is more light weight and I couldn't be happier with it.
If I were you, going for my first pair of FJ's since the 360's, I would suggest the ICON. You will be very satisfied, you will have never before experienced the level of comfort and "walkability" that is provided in the shoe. Truthfully though, you could not go wrong with either choice. They are both of the utmost quality and comfort.
Glad you have decided to give us a try, you will not be one bit disappointed.