The differences are clear if you train your eye. I'm a developer, not a designer, but the kind of flaws in the image add up on a website if the same "ship it" attitude persists to long. Sneaking in not so good design everywhere will cheapen the look of your site, and much like technical debt, become a huge burden later on.
I used to work for Bing and one of the big issues during my time there was the fact that dozens and dozens of answers (not regular search results, the instant answers on top) had different visual aesthetics and were not consistent. Enough visual artifact had accrued as well, that they just didn't look good at all and made for an uncomfortable user experience.