Webware is similar to Java Servlets in many ways -- the basic architecture was modelled on Java Servlets. The primary difference is that Webware is written in (and for) Python, not Java.
See python.org's Python-Java comparisons
Advantages of Webware:
Python is much more compact: WebwareExampleVsJavaServletExample
Python is more flexible and transparent than Java.
All implementations of Webware are fully open source!
Places where they are equal
Python is nearly as portable as Java
Disadvantages:
All implementations of Webware are, well, only one implementation
Webware is not as portable to various web servers (Apache is used primarily, IIS is used by some, other servers are unknown -- though with a CGI adapter, most would still work)
No large companies are backing Webware