For the last year most of my work has been using dynamic programming languages (Ruby and Common Lisp). I have written about this before but given that programmers are properly trained/educated, dynamic languages simply are more efficient when measured against programmer time. I think that the reason is fairly simple: dynamic programming, meta object protocol, Ruby’s missing method, etc. all make it possible to solve some difficult problems with relatively few lines of code.
I have made a good living using the Java platform (starting with Java 1.0 beta) but I think that it is time to move on. Sure, I am still likely to take on interesting work even if it has to be done in Java, but I think that both Java and the .Net platform languages missed the boat on programmer productivity.
I have a few comments on Ruby vs. Common Lisp also: the beauty of Ruby is that it is a simple language to learn and to master. It is difficult to find programmers who are willing to make the effort to master Common Lisp and CLOS. Too bad, but that is the way it is. Personally, I still like Common Lisp a lot because I have already invested decades (part time) learning Lisp and Common Lisp blows Ruby away performance wise. BTW, my positive comments on Ruby and Common Lisp largely also apply to Smalltalk.