I prefer assets that make me a high return for the lowest amount of work possible (semi-passive involvement). And assets that pay me in several unique ways. Cash flow is only one way RE makes money for me. I also get principal reductions, appreciation, tax advantages (depreciation), and I control the rental increases on a yearly basis. Plus a majority of the capital is provided by the secondary market on 30 year fixed low interest rate debt.
One aspect you might want to add to your scoring is “inflation protection”. At one end, bonds and CDs generally pay a fixed nominal coupon that doesn’t rise with inflation. Stock dividends and Real estate rents (and underlying property value) tend to. Not reallly sure how P2P lending ranks- though I suppose the timeframes are fairly short (1 year or less?) and therefore the interest you receive takes into account the current risk free rate + a premium for your risk. Now that I think about it, P2P lending probably deserves a lower score in the activity column than bonds too (since you probably need to make new loans more often).
In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.