Would you also agree that money is a poor motivator for producing good code?

Money might be a poor motivator, but it beats starvation. It takes a serious investment to become a competent programmer, an investment few will make unless they can support themselves with it.

I actually think money is a pretty good motivator. The problem is the work environment that comes with it. Hackers want to put on a high wire act, always trying new, exciting, and potentially risky things. But the guy with the checkbook, all he wants is for the trains to run on time.

Bottom line, in order write good code, you have to motivate yourself.

Do you find that the free software you develop overall tends to provide a better learning experience/more fun/more satisfying than your day job?

Sometimes yes, sometimes no. My personal coding projects I do for fun. I let my muse carry me, and do the parts I like, and just enough of the boring stuff to get by. It is nice to be able to follow your inspirations, but if there is too much boring stuff, I'm not having fun anymore, and I put it on the shelf and go do something else.

At work, it is a lot different. People are relying on my stuff, so I don't have the option to pick and choose what I want to do. Glossing over logging or error handling or version control will get me an emergency page at 2am. So I am more disciplined about doing the unfun stuff, and when it gets to me, it helps to have some motivating factor other than enjoyment. Coding at work might be more constrained, but what I end up with is more robust, and is more likely to actually get finished.