Brian Walsh , Jan 09, 2000; 07:06 p.m.
If the "MTF results" you cite ("about 2.6 out of 5" vs. "3.5 for half the price") are from photodo.com, you might go back there and check how the folks behind that site think you might best use the numbers that they generate from the weighted averages of their MTF tests. I don't think that such numbers are at all useful when comparing very different focal lengths or focal length ranges.
I've been car shopping recently. I give the Audi TT a 4.9 out of 5, while a stolid all-wheel-drive Volvo wagon rates a solid 4. Based on the higher score and the lower price, I'd say the tiny sports car is the clear winner, but my wife seems to think the family wagon might be more useful in a wider range of applications. She also thinks I shouldn't compare apples with oranges.