Valley Investors appraisal of Ruby on Rails?

We are working on a complete overhaul of a consumer internet site that currently has around 200K unique visitors per month. We are confident that the updated design and functionality could get us to millions of uniques per month.The site will also support user uploads of images and other files. We are obviously concerned about scalability and performance, as well as speed of development.

The current version is 10 (!) years old and runs on MS SQL and PHP. The database will migrate to MySQL but we are wondering about coding in Ruby on Rails OR(!) ASP.

We have input for this decision from a technical perspective, but engineers and developers typically promote and defend the technologies and languages that they have the most experience in. There is limited information about this dilemma online. The same story of Twitter moving away from Ruby for performance reasons keeps on popping up.

I am looking for more independent experience and opinions. I am specifically wondering what the consensus is among the investor community. I would love to hear from professional (tech) investors if, for example, they have multiple scalability success with Ruby, or perhaps they do not invest in startups with Ruby on Rails systems for good reasons, etc.

Thanks in advance for your answers!