It is not the language that makes the code, it is the programmer behind.
There are many good and bad examples in both Java and LotusScript. I've seen Java-Agents with hundreds of codelines in the main method, as well as niceley structured OOP-LotusScript code. Additionally, if you count in Formula-Language it gets even more funnier.
My answer to Jakes question is: it depends ... :D
Personally I like the superior Java-IDE, so I tend to write more Java-Code / Managed-Beans. SSJS is also nice, but IBM - why this horrible Code-Editor ....