Smyke - when buying kits, consider only those components that you know for sure are 1) necessary, and 2) good.
I don't know much about this PWM controller in 200W kit. Seems like very basic. There are better ones around, for $80-120. I don't know but suspect nothing good about their mounting brackets as well. I rarely see solar cable in proper length or gauge in such kits. Alright, included Y-splitters you will need, and they are not cheap. So what are we left with - 200W panel with basic controller for total $300?
Doesn't sound too bad, though nothing to be excited about, either. Shop around.