Just curious! about different viewpoints around the globe.

Hi,
Once I was assigned to design a realtime online exam website and I decided to use Node.js and MongoDB for 2 reasons: 1- Node.js works perfectly with Socket.io (for realtime connections and updates) 2- MongoDB is not an RDMBS which makes it really fast for realtime connections and its schema can change pretty easily. MongoDB doesn't have a strict schema actually, you can even have different columns for each record (Not encouraged though).
Node.js is very much able to respond to millions of request per minute. Python is a good programming language and Django is awesome. But as far as I know, Python is slower than JavaScript. So consider this as well.
I think your situation is somehow similar to mine back then. So I hope this helps you.

I would almost always pick Django with Postgres first but your realtime updates requirement makes NodeJS the better choice. For large scale projects I find Python + Django a much more pleasant coding experience. NodeJS, though, makes hooking up sockets to the UI for pushing updates very simple.

A CRM app will have so many objects like Accounts, Leads, Opportunities etc. There will be xomplex relationships between these object if you need an effective CRM. I dont think Mongo will be a good choice for such complex DB relationships. You will need a relational DB. According to me best choice will be Django with PSql. But there are other aspects to consider too like how do you handle file attachments. So it may be good to have a combination and break out the application in multiple components.