I finally got around to PID tuning my CR10S after installing the EZBoard. I definitely recommend doing this, regardless of your machine. Especially if you are seeing your temperature fluctuate on your hot end. I was seeing it fluctuate anywhere from -3 to +3 degrees, and fairly wildly, almost reminiscent of the a year ago when Creality was shipping boards with bad capacitors! Fortunately, you don't have anything to fear. After PID tuning, my hot end temp is staying completely locked in. I maybe see 1 degree change, but rarely.
The default PID's are probably NOT going to work well. I think this is because the MOSFET's used on the board are much more powerful than the average 3d printing board out there. (This is actually a good thing).
PID tuning isn't really that hard, but it does take a little work. Here is a good article that explains how to do it. You will need to have something like OctoPrint connected to the printer. If you don't have OctoPrint, you can also use Pronterface or Simplify3d.
The original PID's in the firmware are as follows:
P22.20 I1.08 D114.00
New pids that worked for me (yours may be different!):
P13.08 I.82 D52.38