Very good ideas to value a cryptocurrency investment. I think even if we just look at the ROI of the POS coins it is already a good indicator if the investment is profitable. Lets say 5% interest a year like PIVX. So if the price stays the same I make 5%. If the price of PIVX drops 50% than I have to wait at least 8 years to get brake even when I'm using the re-invest method. So therefore I know my risk and potentail profits. If the price raises that would be considered all bonus money!!!