When we tried to buy a duplex in Los Angeles with an unpermitted 3rd unit our lender would not lens to us unless it was vacated.  

Also, they broke the skylight lens when attempting to clean it...

Ultimately you will need to look at what makes sense for you and you expectations, and that lens should be how you evaluate any property you look at.  

There are always possibilities of major structural damage.How do you know it is free and clear from other lens or possible tax liens?

You have to be able to see the sale from the lens of both the seller and the buyer in order to get the best deal. 

Please understand the data source and lens of interpretation.Discernment, interpretation, verification and discussion of market or property information is an invaluable skill I provide to you as your agent.Maybe you are just learning about how to use secured revenue sources to provide a down payment for an investment.

@Sean Ray you partner up if it makes sense for you financially in whatever time frame lens you are looking.  

Often times they're buying deals themselves and can share a ton of perspective from both an agent/investor lens. 

With the large employers (Nike, Intel and others), the west side from Beaverton out to Hillsboro is a great place to invest if you have a long-term lens. 

Admittedly, it's hard to see it through that lens at first