When I first got the lens, I was impressed with the build quality. It makes it a bit heavier than other lenses, but once I got used to it, I didn't notice it at all. I guess the fact that it isn't really long makes it easy to balance in the hand.
I took a few pics with it and I am very happy with the results (see below). The animal eye focus isn't 100 percent accurate (though, I have dark dogs with dark eyes) all the time, but I feel like it hit more often than not and when it did hit, I got a very nice, sharp image to deal with. The picture of my pup with his tongue out was only my second post on Flickr with this lens and it get chosen on Flickr Explore.... a rarity for me, anyway. The picture quality is so good that it gets a permanent spot in my bag.
I should mention that I have always been a fan of the 85mm. I have only had two prime lenses in my past and that was an 85mm and 50mm. The 85mm, for me, is the sweet spot for good looking portraits and the low light capabilities mean I can get really nice shots indoors when I need to or melt away a background.
At this price, I am pretty amazed by this lens.
For full disclosure, I received this for free in exchange for a review (for Amazon) and I get paid if you click and buy from Amazon links.