I've never used the card system since I've only taught upper grades.  This is I'm teaching a 2/3 combo so I thought this was a nice chart.  It is very colorful and serves the purpose.  Keeping all the cards straight is a pain since there are the car/bus card and then the set of colored cards in each pocket.  I don't need the car/bus cards but I use it to keep the colored cards to one side so you can actually see which color the kids is supposed to be on.  THis is also on for 30 students=(  I teach in CA so classroom size is usually more than 30.  I have 34=(  I just had to make 4 additional pockets and cut out colored strips.