In general, I think XHTML was an improvement over HTML.  But if you’re looking at a site with lots of legacy code or starting a new project with untrained web developers, you’re likely to get questions: which should we use?  Is it worth spending extra effort for stricter web standards compliance?

Below are a few articles comparing and explaining differences between the two, from the least to the most technical:

• Ask the W3C: HTML or XHTML?
• W3Schools XHTML vs HTML
• Web Standards ROI
• XHTML 1.0 Specification: differences between HTML and XHTML
• Better Living Through XHTML