Yes I have tried both. But I'm partial (bias), I had set up phpBB for several other people and was familiar with it i.e. had experience so it was easy to customize.
I only set up one Invision Board because I needed to use it for a HTML tutorial site. Invision board allows more HTML tags while phpBB restricts the tags (and you must 'define' the ones you want available).
But otherwise, I find phpBB easier to configure / manage (possibility because it has fewer features). But I did not need any of the extra features (such as ipchat) that you can find in Invision
Some people will warn you about a security issue with phpBB – but it's not a problem if you follow the instructions when you install the board. Besides just 4 days ago, Invision had a security warning – security problem.
Footnote: For Invision board owners, I've seen about a dozen probes on my Invision board this past weekend - - trying to find the file with the security hole. But I did not have the ipchat.php file uploaded. If you have not replaced your ipchat.php file (or deleted it) – be sure to read:
http://forums.invisionpower.com/inde...ST&f=1&t=50070"
Back on subject: IMHO phpBB has all the features that I need and the 'admin' is much easier to work with than the one in Invision. Reminder: I haven't spent much time trying to learn Invision - because I already had phpBB experience.
I've read reviews saying Invision is better but I think most of those people are talking about the full install with the ipchat (the extras' IMHO