Summary: I have this lens for about 2 weeks, so I am still all excited about using it. Have had the opportunity to take landscape pictures in deserts and very narrow spaces. Overall performance - great colors, very fast focus, very little distortion, almost no "fish-eye effect", very light (lighter than same A-mount lens for Alfa cameras). Great option for ultra wide panoramic pictures, self portraits (using go-pro poles), portraits and action photos!!
Pros: fast focus, fixed 4.0f, noticeable but very little distortion
Summary: As far as the E-Mount system goes, there aren't a lot of options for wide angle lenses. The SEL1018 however fixes that problem by going Super Wide. Although with a focal length of 10mm on an APS-C Sensor makes it actually 15mm on a Full Frame camera, it is still wider than any other E-Mount lens out to date. The only thing that I would say needs to be improved on is the f/4. Idealy I would like it to go a little lower, like around f/2.8.