One of the most important factors in the Freemium model is to make it very simple and obvious to know the different between the Free version and the paid for model. Seems obvious but many companies don’t. One of them is, you guessed it, Microsoft. I’ve been using the free version of their visual studio tools for over 6 months now and I’ve still no idea what the paid for versions do which is better. I know some things don’t work that well with the free version but I can’t be certain they’re any better with the paid for versions so I haven’t upgraded.