Hiphop doesn't really compete in the same space, as it only converts a subset of PHP into C++, and has very limited support for various PHP modules. I don't think any of the common PHP apps like wordpress, joomla, etc work under hiphop. Stuff like Quercus is the jruby of PHP, being an actual implementation of PHP rather than a source -> source translator. But I haven't seen any benchmarks showing it actually beating regular PHP. It does have a much better security record than the official PHP though, and is probably a worthwhile project on that grounds alone.