I work primarily on the usability, SEO, and performance testing side of things, and recently I've had a few clients ask about Drupal in regards to SEO in particular. Can someone point me in the direction of some resources, or hopefully share your experiences regarding the pros/cons of Drupal development in this regard?
I found a few plugins that "help" with this kind of thing, but I'm looking for some insight on a more fundamental level. In other words, structurally, load time, code validation, etc. How easy is it to customize to ensure everything is spidered properly and productive code changes can be made?