ISO 12233 chart image quality samples and vignetting test results are now available on the Canon EF-S 18-55mm f/3.5-5.6 IS STM Lens review page.
Compare this modestly upgraded lens to its predecessor, the Canon EF-S 18-55mm f/3.5-5.6 IS II Lens.
Update: 18-55mm STM Lens Distortion test results are also now available.