It seems pretty obvious to me that you should use the miles.

But remember that these calculations are subject to any individuals preferences which only you can decide. if for instance you are the type of person that says "I insist on traveliing first class or business class and I will pay whatever it cost me" then the value of a mile to you will be pretty high. Why? Because you will be paying 8K for a ticket to Europe and therefore a 100K mile award will get you 8 cents per mile.

I however would never pay that kind of money for a business class ticket and find it almost impossible to get even two cents per mile. My best case scenario for using miles is probably a $1000 ticket to Europe in the summer for 55K miles. Or maybe a $700 ticket to Hawaii for 35K miles. At best I am getting two cents a mile and really its less because I have to deal with highly limited availability and also the miles I lost by not buying a ticket. That's why for my personal needs I really have trouble justifying more then 1.2 cents per mile.

You need to ask yourself what will you use the miles for. If you would pay serious bucks for a business ticket to Europe or Asia then the miles might be worth a lot. If you don't care that much about premium class travel then it's hard to get that much value from miles and I think that its obvious you should cash in miles here.