The home page would be a lot more compelling if it was easy to find code examples and a tutorial--digging around all I could find was a rather opaque (at least for a beginner) reference manual, and I had to click on the "screenshots" link before I could find examples of what Ciao syntax is like and how one may put a program together in the language. The "Other Documentation" has a bunch of self-labeled out-of-date items and rather academic papers in PDF format. Not ideal!
It's too bad because this sounds like an interesting language which I'd like to learn more about (which I still will, don't get me wrong).
This appears to be a rebranded Ciao Prolog (Ciao Prolog sourceforge page now links its project website to ciao-lang.org). Ciao Prolog was a good performant implementation of Prolog although I use SWI-Prolog myself so can not attest to that personally. Constraint programming (various libraries) and object system (Logtalk) should be available through libraries and are therefore available through SWI as well (though last time I checked ciao has an interface to gecode but not SWI).
It's too bad because this sounds like an interesting language which I'd like to learn more about (which I still will, don't get me wrong).