I epined on If choosing the web framework is a big problem, think yourself lucky.
I know many people will disagree with me. Especially those that write web frameworks ;)
But:
f you think that the hardest part of the project will be the web piece, and hence you end up arguing about framework A versus B until both sides are blue in the face, I would consider yourself very lucky. At the end of the day, the web side is pretty easy with any of the modern frameworks. You will be able to get the job done in admirable style no matter what you choose. After all, what are these frameworks doing? They are hiding the stateless web architecture and letting you display info in HTML, and push back posted data to a datastore.
Compare that problem to the application which has a really tough algorythm? I am currently working on a project which has a need for near-AI on the server side. An agent will be watching what a user is doing as they traverse the web site. It will be collecting data from the user (based on input, and via what the user does) and then has to go through a set of complicated business rules to give a smart response. Are we spending time worrying about which opensource web framework to use? No. We are focused on the complicated business logic.