Waterloo is probably the hardest optometry school to get into. It's the only English-language Optometry school in Canada - supplying the optometrists that serve a population of probably 20 million. Also, being within one of Canadas top universities makes its a research intensive place... they even collaborate with the faculty of egineering. As for acadmic requirements, I think its also the hardest, although UC at Berkley is probably very close. Last year the average grade of successful applicants was ~85% ( GPAs of 3.8-4.0?) and the average OAT was a 360, although I don't think they're too picky about the OAT, 310 or 320 will do.
As for reputation at the undergrad level, University of Waterloo is one of top in the country, with the likes of UofT, UBC, UWO, Mac, Queens, among others... and was recently ranked #1 comprehensive university by Macleans Magazine and also won "best overall," and "most innovative" reputational titles.