Hi,
I my opinion, I would say CRM would be a better solution, since it's built to handle cases like yours. You can easily store data relating to your clients and employees of your clients. It can easily derive reports out of the customer data that you have.
However, for documents I would suggest using SharePoint. If it's a lot of documents that you manage, you can have both CRM and SharePoint and the integration is pretty simple and comes OOB. If the number of documents are less, you might as well use the Notes
(Attachments) of CRM. To wrap it up, CRM is for Customer data whereas SharePoint is a document repository.
Admin QuikView Solution for CRM 2013