I have made an unboxing video on YouTube, Theo Xydias. I got it for both amateur and professional use. Initially, I was going for the Tokina 11-16, but after seeing comparisons, I ended up with this one. It has incredible sharpness, the autofocus is lightning fast, and it performs amazingly in low-light conditions. It is the best choice for a crop sensor, especially if you're photographing stars. I also use it for in-car videos, capturing the entire front of the car. From me, it's a 10 out of 10 lens. Combine it with a Hoya UV/ND filter and you won't regret it. Lastly, some people mentioned the weight. Okay, it weighs 502 grams, but you don't need a crane to lift it.

I was torn between the 11-20 and the 11-16, like many others. In the end, I went for the 11-20 and I am extremely satisfied. Great sharpness. The extra mm it provides are almost necessary for me to avoid changing lenses. The 11mm sends the subject very far away. For astrophotography, both the 11-20 and the 11-16 are top lenses for crop bodies.

The lens is relatively heavy, which doesn't mean it's a disadvantage. This happens due to its sturdy construction and the glass it carries (82mm diameter & f2.8).
The sharpness is equally excellent, especially from f5.6 as mentioned in reviews on the internet, without lacking in wider apertures.
As for its "downsides" (which in my case, don't concern me much with what it offers me, hence the quotation marks).
The autofocus mechanism is slightly noisier than Nikon's "silent" ones and a bit slower. Personally, it doesn't bother me at all, as it is at very acceptable levels even for enthusiastic photographers. It has also been proven that many third-party lenses tend to be slightly slower but with much better sharpness performance.
As for me, I consider the lens to be very good and worth its money. I highly recommend it.

Update 24/10/2019
The lens has performed exceptionally well in indoor and landscape photography where I have used it. Together with a HOYA ND1000 filter, I have taken beautiful long exposures.
I encountered a focusing issue through the camera's Live View (Nikon D7200) and it was sent to the authorized service center (it was just before the 2-year warranty expired). It took 1 month since it had to be sent abroad. The staff at the service center in Greece were polite, professional, and tried to resolve the issue as quickly as possible. Even the official Tokina Facebook page responded almost immediately to my inquiries regarding the service process.