The first version of our website was running OpenACS, when we launched Virtualmin as a product. It's suffering from second system effect in pretty terrifying ways. Of course, we then jumped ship to Joomla, which has a nice core but the modules are of wildly varying quality, and so ended up regretting the move, as its problems were even more pronounced and harder to fix than OpenACS. We finally settled on Drupal earlier this year, and have been mostly happy with it.
That it was written in Tcl was actually not among my many complaints about OpenACS (though there are languages I prefer, Tcl is acceptably sane and acceptably powerful).
OpenACS is a bit of a beast. AOLserver is a very nice bit of work, though. It's a pity it wasn't released as open source sooner, as it is a very nice system for creating dynamic content.
Agreed. I really enjoyed AOLServer. It was rock solid, really fast and reasonably resource efficient, did everything we needed for our particular deployment, and was reasonably well-documented.
But, it also had some limitations that made it less promising. It was intimately tied to Tcl, which is, let's be honest, not growing in popularity, had some old school architectural choices that would limit extensions and be hard to overcome (Apache had a lot of the same issues early in its life, but overcame them through brute force...when there are hundreds of active developers, all problems get smaller). It was designed for a very specific purpose, and it showed. So, I don't think it's a codebase I would consider spending time or effort on, if I didn't have really strong reasons for sticking with it.
