This article was only able to take a look at Water compared to Java in writing a simple file server. Because Water is built on a Java foundation, programmers can drop down to Java to write code through a specification called Water Bridge whenever Java is needed for an extra boost of power.
The ability to quickly implement common web service processes makes Water an excellent choice for rapid prototyping and concept testing. Water also has a built-in testing facility that allows the programmer to run code against a test suite to verify and validate the code.
As you're wading through all the new web service products vying for your attention, take a look at Water and the Steam XML IDE from Clear Methods. Chances are that you'll find something that amazes you.