I feel obliged to mention the caveats of the posted spreadsheet. The calc shown were done with some narrowly defined assumptions which may or may not apply to your personal situation. Would you ever spent $100,000 on hotel stays and if so, within what timeframe? If you choose to double dip on an airline partner with HHonors, would it necessarily be BD? The $100K assumption was used to demonstrate the calc, it could have been $10,000 but then the number would be too small for computing Marriott travel packages, hence making the comparison incomplete. While BD offers 1,000 miles per night up to 3 nights within a stay and its miles have some of the best value for money - for someone who doesn't ever leave the country, its value may be under-appreciated. Someone told me recently his double dip partner is Southwest, an airline that I have personally never set foot on and likely never will, so again, YMMV. From a financial standpoint, choosing BD makes the most sense numbers wise, from an objective standpoint but some folks may not appreciate that due to their personal circumstances. For me, even if you live in the U.S., you can make great use of BD miles by getting award tickets on UA and US, hence I don't understand why someone would want to put miles to Southwest instead but then again, not everyone likes the Marriott travel package either since it reduces the number hotel nights they can have and they may not want airline miles at all because they have more than enough already.