Azul is somewhat different, I think. It's on par with other commercial JVMs like Excelsior Jet with aggressive optimizations and inline compilers. Azul (zing vm) uses LLVM to produce JIT, if I recall correctly.
But yeah, there is too many ways to install JDK/JRE nowadays. I'd like to use OpenJDK everywhere possible, but in terms of raw performance it loses so bad to Oracle, it's just unwise for production.