My sons school used this. He's now 18!
Hated it then and hated it now.
Mainly hated it because you could go up from the sun to rainbow.
You could go down to cloud, grey cloud and then black cloud.
I don't disagree with charts and visuals at all. They are very helpful in motivating and reminding children to adhere to expectations.
But imo they should be balanced. You shouldn't be able to keep doing wrong without the opportunity to equally keep getting it right.
However it maybe how the year R teacher used it. She would move children up very infrequently and wouldn't move them at all for behaving. She would however move just turned 4 yo down for doing things a 4yo would be expected to do without any sort of chance to improve.
One example being the HT asked pupils in assembly what the picture she has was of. Stood right in front of my ds (4yrs and 3 weeks old) he assumed she was asking him directly and answered her without putting his hand up.
He went down to cloud when back in class.
Then it was wet play and because he was in trouble spent the whole break tidying up the bookshelf instead of playing to try and go back to the sun.
When teacher returned to class she told them tidy up time. He went to tell her and got moved down to the grey cloud because he went to talk to her instead of tidying up (the toys he hadn't played with).
As you can tell it bothers me over 14 years later and sadly it shaped his first year of school and by Christmas was asking me why he was such a bad boy. 
I'm a strict parent! I expect children to behave. But you have to balance out expectations with the praise and reward and time to listen to encourage the behaviours you want to see.
A solely punitive approach doesn't work.