That is what will happen. You will spend time and money getting a good rep and your clients will tell their mates about you but most of the referred people will end up going to the .com.

Having the .net is not ideal and I would recommend against it.

Also what happens when the owner of the .com decide they want the .net and your using the domain for the same purpose as them?

EDIT: I should have paid more attention to the date but I am pretty sure it was top topic.