That not all web code is created equal. It's true —
standards-compliant XHTML code that is "semantic" in nature and uses externally-linked ("load-once") Cascading Style Sheets (CSS), generally, provides a faster and better viewing experience over a wider range of browsing environments.
Unfortunately, many "professional" web designers continue to use the old "table-based" HTML way of doing things — knowingly or unknowingly leaving their clients with web sites that are obsolete the day they are launched.
At JRS Solutions, we recommend and use standards-compliant code. We also strive to help educate our clients, so they can make better informed technology choices.