I'm currently building a working prototype of my product for my home business. Without giving too much away, it is a product you can use around the house to make maintenance a lot easier and almost fun. I think the market will be strong for these reasons.
Here is my issue. These units are already on the market but in very small pockets. They are not mainstream. In fact, I've never physically seen one, just some pictures and videos on the internet. I want to change that by making my own similar product and start selling it.
I can't patent this as the product already exists in the world (albeit on a very small scale), so how do I protect my business once I start selling these units for real? What stops other companies from making the same thing and running me OUT of business?
You can always patent design. So you could patent certain form factors, or ways people interact with the device or maybe some part of the system or device. Could patent the interface the user uses to interact with the system. However, these will be patent pending for 5+ years cost a lot of money to push through and be easy to maneuver around by any competitor.
So - as I and many people feel about products and software the best way to not get run out of business is to do it better then anyone else. If your product is superior, reaches more people, you're are conscious about your production costs you should be able to stay competitive and lead the market.
Nothing pisses me off more than someone who files a patent with no real intention of trying to change the world with it.