Fantastic looking with our quartz countertop.  Very easy to install with clear precise instructions.  No you do not need a plumber.  Had to remove the water saver feature  as it did not provide sufficient pressure for the spray.  Working great now. Well packaged for shipping. 
The reason for the four star rating is that you have to occasionaly tighten the water lever which screws on the assembly.

Very satisfied with this purchase.