Yes, they are two different currencies, but the total reward value per dollar is relatively similar.

Starpoints are worth far more than Marriott points but again the total reward value per dollar is reasonably similar.

The three programs all have slightly different sweet spots: maximizing value is somewhat dependent on whether you intend to pursue those specific awards (e.g., the Marriott Travel Packages, etc.).

I still think the Hampton/Homewood mix would be enough to keep me at HHonors, even though I do love the Marriott TP's... There are some pretty bad Fairfields out there. Since many people do Fairfield/Hampton stays sight unseen (picking one while on the road, no ability to research the specific property other than perhaps a drive-around), the overall confidence in the brand is more important.