You do not have to use the stock CDI in order to make your scoot run well, you can use others. The video posted here I made over a year ago so that you can listen to the scoot with each in operation. You should be able to hear the difference.
The non-stock CDI has a slightly different firing point and advance curve from the stock unit, so the scoot feels and reacts a bit differently. Overall, the stock unit is “better” in my opinion. I run the stock unit. The other is a spare, and should the stock unit fail, I will be running again very quickly.
By “better” I mean more pleasing to my scooting experience. Of course, the stock unit is also better because the engine (specifically the valve train) were designed and engineered for the stock ignition timing.
So that is two different styles of better.
Be careful, as better is one of those words that each person defines in their own unique way. Many people apply a moral meaning to these slippery words, as in right & wrong. You can find that you have offended their godly and righteous view of the universe at which point they might kick your ass. 
