The EF 28mm f / 2.8 IS USM is a compact and very high-quality processed fixed focal length lens with a useful focal length, maximum aperture and a good modern image stabilizer which achieved a profit of 4 f-stops f-stops. Even if the image stabilizer definitely has its uses, but it is generally with wide angle lenses less necessary than in telephoto lenses. The lens is also suitable, as for architecture and landscape photography for shooting in tight spaces. On an APS-C camera, the lens has an effective focal length of 45mm, which is roughly equivalent to a "normal lens" and therefore is also suitable for a variety of applications.
In terms of image quality, the lens does not have to hide - it is already neat sharp at f / 2.8 and also shows only low distortion ("distortion"). My lab tests did indeed fringing ("Chromatic aberration"), both visible in focused ("lateral chromatic aberration"), as well as in blurred image areas ("longitudinal chromatic aberration"), but these are compared to similar lenses of acceptable intensity. The focal point of the lens has no curvature on (no "field curvature") but edge shadows ("Vignette") are - even dimmed - clearly visible.
The EF 28mm f / 2.8 IS USM is priced similar to the EF 24mm f / 2.8 IS USM settled, but will cost considerably more than the EF 28mm f / 1.8 USM, which but an even better maximum aperture offers no image stabilization has and also in respect the image quality can not keep up. On the other hand, it is by its light intensity for available light shots much better suited as the EF 28mm f / 2.8 IS USM.
If you already have a zoom lens covering 28mm focal length, the EF 28mm can f / 2.8 IS USM still be interesting because of its image quality, compactness and good maximum aperture of f / 2.8.
Is the EF 28mm f / 2.8 IS USM the right lens for you? I think it very much depends on how you define your "objective Park" build it. If you can use the focal length / full-aperture combination, will not disappoint you the high quality of workmanship and the good image quality of the EF 28mm f / 2.8 IS USM.
A much more detailed report I published together with all the test shots, specifications and sample images on my homepage LensTests_de.