I have an excellent DA 55-300 and an average DA*60-250, I'm pretty sure I can prove the DA 55-300 is better than my 60-250.
That has been a point I've been trying to hammer home for the better part of 10 years now. If I'd had the 30% number I could have gone to Optical Limits or any testing site to demonstrate that.
I have never seen any evidence that the "I have to have the sharpest lens out there" folks ever take better images than those of us cheapies who buy the best lens we can afford for the job we want to do.
They assume their lenses are better because of test charts. But their images don't support that.
My biggest objection to posts on the forum come from lens snobs. "My lens cost 5 times as much as yours did, my pictures are better." They remind me of the snobby kid from high school going on about how much everything he owned costs.
If I don't like your images, how much you paid for your gear means nothing.
The silence when that guy won the Flickr image of the year (from the "I own the most expensive lens ever" crowd) with a K-x and kit lens was deafening.
I probably have spent 10 times what that guy has spent on equipment, yet none of my work was even considered.
The guy is a champion. And proved what many have said endlessly. Right time right place with a capable camera beats expensive high end gear every time, and produces better results.
I can hear the high end chorus. "But if you shoot the scene with an average camera and I'm there and shoot the same scene with my expensive gear, mine will be better.'
Yet in one of my tests my lowly FA 35-80 was judged better on exactly the same image by twice the average lens and led the pack, when viewed as an image, not pixel peeping.
Expensive big bucks gear is not the advantage gear snobs claim it is.
People need to get out there and shoot with what they have. The advantage of more expensive equipment is supported only by hype and bluster. You can still win the Flickr photo of the year with an antique sensor and a kit lens. And while those of us who have spent more money may think we can do better, most of us haven't.
To a certain extent, I buy lenses I think I will enjoy using. The whole IQ based on test chart conclusions thing is focused on way too much.