I have never tried this simple knife sharpener.every knife needs to be sharpened no matter how expensive the knife will be. Here are my pros and cons of ninja foodie

Pros
-easy to use
-sharpens the knife pretty well
-easily available
-very well-made
-comes with instructions on how to use the knife sharpener 
-it’s pretty straightforward, simple and effective product.
-knife has got very good grip . 
-it comes with one knife but if u have ninja knifes u can use them too for sharpening.
-now I can cut my tomatoes without squishing out.

Cons 
-a bit expensive for just one knife but worth the money we put in . 

My cutting /slicing time has come down . No mess with the sharp knife . The maintenance on this thing is so minimal. It works for me . 
Overall I am very happy with this knife and the sharpener system. I would totally recommend it.