I love this concept, and I can see my business using it. We have three team members, so I'm surprised you consider us an Enterprise. I'd be more comfortable if you called us a "Business" or an "Agency". And should a true enterprise be capped at five users and pay just $69 per month? If I were to sign up, I'd get an Advanced plan and deal with just having two users.
As a business owner, this product solves two needs: 1) saves lots of time and 2) ensures that salespeople can assemble good looking proposals.
Do you have example proposals on the website? I want to see what this generates without creating a free account and doing a bunch of work myself.