This is a good quality filter, at a very reasonable price.
Having spent a lot of money on a new lens/camera, the first thing you really want to do is to get a protector filter. It's true that there is a debate by enthusiasts as to putting a comparatively cheap piece of glass in front of an expensive lens. That's why you go for the best you can afford.
To me, there seemed little reason going for something more expensive than this. It's a case of diminishing returns. My old Nikon 50mm lens was quite recessed, and didn't require much protection, but having bought the Nikon 35mm f1.8, the glass is quite close to the front. Perfect for knocks, scratches and finger prints!
I tried taking some sample pictures with and without the filter, and to be honest, even at pixel level I was struggling to find any difference. The colour rendition was identical, and I didn't notice any flare or C.A.
This is quite a slim filter, so didn't show any vignetting. Obviously if you add more filters on top of this, you'll get to the point where you do though! If you're going to be using a polarizing filter all day, take this off and leave that on.
Similarly, if you're worried about the quality for those 'special' pictures, take it off for the duration. A protector is more for those 'quickly get the camera out of the bag' or 'strolling around' shots anyhow. You wouldn't use it in a studio!
The glass is clear and doesn't rattle in the metal frame. Threads are smooth and the whole thing is quite light.
Hoya have a good reputation, and for good reason.