What are the most important features we should be looking for in an engineering document management system?

Answer 1

I usually get $125.00 an hour to answer a question like this, but let me point you in the right direction.

Questions you need to ask?
What is the amount of documents stored on a daily / weekly basis?
Who is to have access to it?
Do clients and / or staff need access to it from remote locations?
Will multiple offices need access, and if so, are they on the same network? Does it need to be accessible over the Internet?
Will the documents need to ever be faxed, and if so, should the system have fax capabilities?

Give me some additional information, maybe I can help you narrow this down a bit.