There's no other 28mm prime for Canon worth looking at; this is as good as it gets for Canon. Sharpness, contrast, flare resistance, and corrections are nearly on par with the 24mm f/1.4L and 35mm f/1.4L lenses. Focus is fast and quiet, as is the stabilisation. Build quality is not up to the standards of those L-lenses, but is still sturdy and more than sufficient for this price point. The only other Canon 28mm prime is the 1990s 28mm f/1.8, and while that lens is a stop and a third faster (though gives only three quarters of a stop more light; its T-stop is quite far from its F-stop, unlike the f/2.8 IS which is also t/2.8), every copy of that lens I've owned or tried has been extremely soft in the outer half of the frame, even when stopped down to f/8; the f/2.8 IS is sharper wide open than the f/1.8 is stopped down.
If 28mm is what you want for a Canon EF-mount camera, this 28mm f/2.8 IS is somewhat your only option, but luckily is also superb in its own right.