Marriott points don't only need to be used at Marriott properties. You can also trade them in for miles. Using travel pakcages, you get miles plus reward certificates you can use at Marriott hotels.

There is value in flexibility too. In that regard, I really like starwood points. They can be used for hotel stays, which is a great value, and also can be exchanged to a number of different airlines.

As for the value of points, it's tough to say. I wouldn't use a starwood point for less than 2.5 cents per point. At the same time, I have 50k CO miles that are sitting there gathering dust that I got pursuant to a promo. I don't accumulate CO miles to the point where I'd ever get a great reward and starwood are a terrible value transferring to CO. So, if I find something good to do with those that I need, I wouldn't necessarily hold out for 2.5 cents per mile.

One hidden cost of using miles is that when you do, you typically don't earn miles on the award. So, for example say you redeem 40k USAir miles for a domestic cross country trip trip during a double mile promotion. If it was a $700 ticket, maybe it seems like you've gotten decent value. But, when you consider that you've not only used 40,000 miles, but also foregone the opportunity to earn 10,000 EQM, just to use miles that could have been used on a star alliance partner at a rate far better than 2 cpm, it starts to look like a bad deal. That's just an example of what goes into it.

But all that said, there're so many variables. A few months ago, I cashed in 240k US miles to fly 4 people to Maui in coach over the holidays. The cash price of the tickets would have been about $3900. That's a ratio that would horrify many people on FT, when you consider those miles could have been used on a star alliance partner for some pretty spectacular trips in J or F, and we forego about 25k EQM miles by doing it as a reward. But all that said, I had a reward hotel cert that I needed to use and there was availability and I have a cert to use for a significant discount on a rental car. So, it's a trip that's close to free and that we wouldn't have done without using the miles. Even at far less than 2 cpm, it made sense for us at this time. Everyone's calculus on this differs.