If your resume will be read by a resume scanning program for key words, it's absolutely imperative that those key words be included in your text. Consequently, tailoring your resume to an ad, networking recommendation or job description is probably even more important than if a person were doing the initial screening. In this respect people-scanned and computer-scanned resumes are very similar. However, because some computer scanners have difficulty reading vertical lines, italics and unusual type fonts, techniques you might use to grab the attention of recruiters can be misinterpreted by a computer. If your resume is likely to be scanned, keep the format simple and use only boldface type and bullets to highlight major points.

We're supposed to be perfect our first day on the job and then show constant improvement.
Ed Vargo major league baseball umpire

There is no universally preferred format. Many job seekers spend days perfecting their resumes, agonizing over whether to use a chronological format or a functional one. This question may be akin to figuring how many angels will fit on the head of a pin. There is no one perfect resume to suit every employer's needs. But there is a perfect resume for a specific opportunity. If you are going to focus on perfection, do it on an individual, rather than a global basis.