There are numerous debate on this topic.  I have been a cashback person all the while and recently have been wondering whether it's worthwhile to switch to miles. However, I have yet to see any concrete quantitative analysis to aid my decision hence I decided to do one myself as I'm an analytical person.
MethodologyI assume we will fly out from Singapore and miles accrual in KrisFlyer. Hence I will base on the latest SIA KrisFlyer Award Chart (effective from Jan 2019) to select the representative zones and the lowest number of miles needed for a round-trip redemption across Economy Saver and Advantage. Based on this post, taxes and fees have to be paid using non-miles.
I also scanned through the miles credit cards for a sensing of mile accrual rates and card annual fees.AnalysisRefer to this spreadsheet screenshot for the analysis (click to enlarge).

Meaning of the columns:Amount to spend: I calculated the...