There are already a lot of good technical reviews out there, so this isn't another. What makes a really good lens is how well it works for YOU. Yes, this lens has some weird distortions that can't be fully corrected (at least not that I've found) and it's manual focus only and doesn't communicate with the camera body, so does manual iris control. Any good points? Well... after a bit of vignette correction in Lightroom (along with as much distortion correction as the profile found allows), the image quality is very good. Most reviewers will advise against using this lens for architectural photography as it has a lot of straight vertical lines due to the mustache-shaped distortion, but that's what I mainly use it for. Sometimes creative manual distortion correction is required to fix wavy verticals. The Canon 17-40mm lens I have is easier to use, more flexible and produces less distortion, but I have some clients who are absolutely adamant about shooting as wide as possible. Is it my everyday lens for work? No, but it's always in the camera bag. It also produces fantastic images of the night sky, stars and all that stuff. For the price, this is a budget lens.