Michael Kimsal has posted his opinion on why PDO, the database interface layer for PHP, sucks.

Every so often I try to use PDO under PHP5, and every time I run in to basic functionality problems with no ability to find out what's going on under the hood.

He includes a few comments supporting his statement including an issue where a prepare() call didn't work, his frustration with not being able to see what's "under the hood" and the lack of documentation to help with these sorts of issues.