What is stopping you from using Rails/Django?

At the last meetup, the majority of the people there were ‘thinking’ about using either Rails or Django on a real world project. So by way of some blatant agenda setting for the meetup on the 10th (don’t forget to go and leave a comment if you’re coming) what is stopping you from using either?

Is it concerns about maturity? Scalability? Deployment options? Does the lack of (development) tools put you off? The lack of a workforce, or simply the fact it is in a new language? Is there some killer feature that either one needs to make you use it? Perhaps if enthusiasts of both communities start addressing these concerns and start engaging in some (balanced) advocacy and honest discourse, the adoption of both can be sped up.