(This is specifically for the red grip. The others may be different.) 1. The Joy-Con grip that comes with the Switch has metal tracks that connect to the Joy-Cons. This one has plastic tracks that feel and look cheaper. Maybe they'll stand up just as well in the long run, but I'll have to see. 2. The red of this grip DOES NOT match the red Joy-Cons that are available to buy. They clash pretty badly. The grip does look okay with the gray/black Joy-Cons, so it's not a complete loss.
Plastic rails and it clashes with red Joy-Cons