Jeremy Cook has put together a quick guide for something that can be tricky when using PDO in PHP - handling binary data in the return from your queries.
I like the fact that if I needed to use MS SQL Server, Oracle or any of the other big RDBMS's I could use the same PDO syntax to access them rather than learning a new database access library. However, there do seem to be some bugs in PDO according to what I've read on the web. While I haven't encountered most of them and can't comment on them I'd like to write about one that I ran into the other day and how I worked around it.
He was storing images in the database and pushing the information into the database was working fine. When he tried to pull the contents back out, however, the information wasn't being handled correctly (according to the example in the PHP manual) because of a differing return value for the fetch call - sometimes it's a string but, in this case, it's binary data so it needs to just be passed on through.