I was reading down this thread and @David Beard beat me to the comment. This is a great strategy on paper, but can become a flawed strategy to execute very quickly and I personally know. The leverage amounts can put you and your portfolio under a great deal of stress and with each successful refinance (if you even get that far) you feel like this is the greatest thing since the dude climbed the beanstalk and found the goose laying golden eggs. Even thinking this strategy can lead to poor decision making like buying subpar deals simply to pull money out and eventually getting swallowed by upkeep, record keeping, maintenance and vacancies in the rental portfolio.
I'm not saying that you are going to go down that path, I'm just saying that many have been seduced by this "get paid to buy rental property strategy" and many have ended up losing a lot.
On a side note, it really concerns me for the real estate market that banks are even starting to think this way and offer this alternative again. This is absolutely why many investors failed from 2003-2008.