Clear corners can look really good (like on BMW's). If used as a subtle accent, they can make a vehicle look better.
Unfortunately, 99% of the time they scream, "I'm in high school" and fall into the same category of Pep Boys-induced gayness as blue bulbs, chrome fuel filler door covers, "No Fear" windshield banners, LED spinner air fresheners, Taz steering wheel covers, and those stick-on fake vent holes for the fenders.
You can be the judge of whether your particular vehicle would fall into the 1% group or the 99% group.