cash out refi to grow portfolio or slower growth?

[Ryan McCook]

I'm really trying to figure out which is the best strategy. I can cash-out refi on some properties and get similar interest rate to what i currently have or even slightly lower interest but I would be starting the 30 year over again whereas I currently have about 4-6 years already paid down. But, I could get a substantial amount of cash out that could aid me in doubling my portfolio, albeit with worse returns given today's market.  Should I continue to enjoy higher returns on the existing property (and grow portfolio slowly), or lower my margins but increase my portfolio size quickly?