JODConverter is definitely a reasonable solution for most applications. You can also write a Python script that leverages OpenOffice's Python UNO API to do the same thing - a basic script that turns Office files into PDF's is only ~20 lines of Python.

For really serious applications, though, you will eventually run in the limits of OpenOffice's support for MS Office formats. If you are very picky (or have a very picky client) about the quality fo the conversions, you'll end up having to use Microsoft Office to do the conversions. This is a lot less pleasant to set up, so I wouldn't do it unless you have to.