But it also depends on whether your management style effects your bottom dollar in a positive, neutral or negative way. 

Also consider the neutrality, as well as how it effects the light and feel of the space.

I can't really decide on what would be best for the trim / ceilings and neutral colors that deliver good value. 

So, my bulletproof investment formula is the following: Maintain at least a 40% savings rate, invest your savings at >8% returns to outpace the real rate of inflation, save until you can afford to put a large deposit down, flip that into a low fixed-interest loan, to generate at least a cash-flow neutral investment return on an appreciating asset. 

My least cash flow purchase I estimated at neutral cash flow but it was an easy decision to purchase.  

A really large flipper outfit will also buy materials at discounts the average consumer cannot obtain.Also, flippers know how to use neutral design choices that will appeal to a wide base of potential buyers.

@Brady Mickolichek - neutral colors and pick one color/finish for your surfaces that will fit for ALL of your rentals.

@Scott Skinger is correct about the numbers. 20% is way off and the boilerplate 50% Rule OF Thumb is a better neutral swag.

However, if I purchase a cash neutral home at 80% LTV then a 7% appreciation materializes a ~33% return on the investment (not taking into account closing costs). 

Robin when I had mortgages on my properties my goal was to have a neutral cash flow.