I think it's super attractive to new businesses to push their wares via a generous free plan. But in the end, unless you think word of mouth is going to take off. Validating your business model by charging is much more important.
Free plans make sense for new businesses that are trying to get users to test a product or service, but once it's been built and is working seamlessly SaaS companies really should start charging.
I really like the idea of having a bunch of litmus tests like this that you can rate just about any business concept against. I think far too often people get married to the first "million dollar idea" that pops into their head and they almost all skip doing this type of analysis. This list is excellent and could save someone years of lost time.
There are some things that I wish I had done differently for sure. Namely looking at competitor price points and understanding the impact that would have on the business.
In my experience this strategy only works with small projects. Projects with any level of complexity will have you running from fire to fire and it will impede your forward progress. Developer retention and customer happiness will suffer. I'd be happy to compete against such a company. ;)