If 10% down can make you positive cash flow, great.
If not put 20% down. If still not enough, put 30% down. What other choice do you have when it comes to investing. The bottom line is trying to put down as little as possible when you can, borrow as much as possible from banks. The even bigger bottomline is not to kill yourself with unbearable negative cash flow. If the negative cash flow is only 200/month, and your income is enough to make that small loss insignificant, then, still go ahead and buy it.

Don’t let small negative cash flow cause you to give up a great opportunity. Don’t let big negative cash flow to kill your financial well being either.

Find a balance point between potential pay back and current loss. I personally consider a small negative cash flow situation like -200/month tolerable. Eventually, after 5 years, the market rent will rise high enough to turn a small negative cash flow into positive cash flow.