quality is still hard to measure. speaking from experience, i've always had passion and personal projects, etc, but i used to be a sucky programmer. now i feel like i've mastered certain things, but i'm still developing and getting better. for one thing, quality comes from sustained effort and committment. i've been working full time on startups for a while. that's a hell of a lot different than someone doing a diffe…
I find that for me, side projects are very beneficial because they give me absolute freedom to try new things without stepping on co-workers toes. I have to agree that metrics don't tell the whole story. It really depends on what the programmer is looking for. Some people may be attracted to new features & complexity in their projects, while others look to design a small simple project.
toying is part of the inventor spirit and different projects need different things. one project might be ok with one of the mockups architects make. another project might need the life sized building. and so on in between, changing as the project grows.