My practical experience from two large projects is that we have spent 1000 - 1500 hours for each project on maven related problems, excluding a 500 hour effort of moving from maven 1 to maven 2.
Since then, I must say that I absolutely hate maven. I am getting frustrated when thinking about it.
The Eclipse integration is awful.
(We had endless troubles with code generation for instance, where eclipse got out sync with the generated code, and required a complete rebuild, quite often. The blame is both maven and eclipse, but eclipse is more useful than maven and say emacs, so eclipse stays and maven have to go.)
We had a lot of dependencies, and as we discovered, syntax errors are actually commited to public maven repositories quite often, wich can ruin hours of your valuable time. Each week. The workaround is to have a proxy or locally governed repository and that took quite some time to get right, too.
Mavens project structure is not really suitable for development with Eclipse, and the build time in eclipse increases.
An effect of the code generation and sync problem, we had to rebuild from scrach rather often, reducing your code/compile/test cycle to an endless compile/websurf/sleep/die/code-cycle, sending you right back to the 90s and 40 minute compile times.
The only excuse for maven is the dependency resolution, but i would like to do that once in a while, not in every build.
To sum up, maven is as far from KISS as it can be. And also, advocaters tend to be the type of people that celebrates extra on their birthday when their age is a prime-numer . Feel free to vote me down :-)
