Right now I'm not able to tell how it is compared to Joomla (which I have used a few times), but I'd like to know why you state both php and Drupal as useless. Yes, I noticed the illustration but a "steep learning curve" doesn't explain "useless". My experience with something that is hard to learn is that you benefit in the end.
In general the good thing about Drupal is the modularity, you only use what you need and thus get a better performance vis a vis Joomla but still have as good or even possibly better availability of reasonably robust add on modules. Lots of available books and web support as well.
It has a lot of quirks though that make learning it a highly annoying experience and what you learn is not applicable to anything else, and the performance gains are relative to other PHP based applications. Structure of the program also changed quite a bit between 6 and 7 making older books less useful than they were.
PHP processing of any kind can be painfully slow with some language features being downright glacial, I have seen my old dual core server die handling as little as 11 "almost simultaneous" requests at a time and a rented quad core with plenty of memory wasting well over 80% CPU time on 12 "almost simultaneous" requests, in both cases done by myself by simply opening up a web browser with 12 open tabs.
An often overlooked PHP based alternative is Typo3, which is structured much better than the alternatives even if it does not have as many available add-on modules and some of those only currently available in German, but the better thought out structure makes the learning curve a lot more agreeable than Drupal's. The only real downside it has is that the Danish fundie that started the project sprinkles the source code with Christian propaganda, which can get irritating when you are bug hunting. (
https://typo3.org/)
Another PHP based alternative is TikiWiki, despite the name a full CMS rather than just a wiki (
http://info.tiki.org), much easier to learn than the others and very fully featured but can be very buggy due to an almost insane development pace and can be bog slow as well if you have all features enabled.
Frankly, all those PHP programs make me appreciate how good and relatively fast the combination of GoServe and REXX was back in the early - mid 90's (
http://speleotrove.com/memowiki/MemoWiki.html)