I used MVC 1.0 for my startup in 2009. That time, not much open-source contribution was seen in Microsoft world, but that's not the scene now.
And in my previous job, we switched from ASP.NET MVC to Django, got a Django guy in our team. Still it took a double the time for developers to pick it [in a way money]. So I say unless technology is not a concern for the product, stick with it and build the product, make it successful, you can switch technology later also.
At the end of the day, customers don't care what platform you used.
If your bro is ready to go with Django/Ruby awesome, but keep in mind time & money before making a decision.