Hmmm... we write some involved reports in Access, with often several complex SQL queries, several levels of grouping, several subreports, heaps of calculated fields which sometimes use data from more than one subform, etc.
I have no doubt that this can be constructed in PHP, but as we'd have to build the equivalent of a reporting engine to construct so many reports, I'm not sure we'd achieve this '"easily".
Two report tools/engines I've found are DataVision (Java based), and RLIB. Both are open source.
RLIB has hooks for PHP, but no design interface (GUI). DataVision is meant to be used in a J2EE environment, although maybe PHP could still use it.
I guess I was hoping for a reply to my post such as "oh yeah, we all use [some_fab_engine], it's easy, has a GUI, and great community support". Don't want much, do I?