This lens is very interesting and fun for the price. I found it doesn't perform great with regards to flaring and shooting into the sun when compared to the Rokinon 12mm that costs more than twice as much ( so not amazing for landscape work ), but this Pergear lens does have some nice sun star effects which could make it a bit more interesting to use for night cityscapes where lighting conditions aren't as harsh.
I was expecting the Pergear 12mm f2 to have a lot more of the imperfections and sort of wild characteristics of their other lenses. But it doesn't. It's actually way tamer, with very nice contrast and pretty good sharpness across the frame. I'm actually impressed. I was not expecting this lens to be actually viable for landscape photography but the potential is there.