I think that there are many reasons to go with the Starwood card.
One of my favorites is the following conversion:

1. 40K *wd = 50K airline 1 european RT/ 2 Domestic RT (you get 1.25 per $)

and those 50K CO/DL = 100K Hilton (If needed) That is equal to 6 nights in HI or non-US hotels.

If you can wait until 60K:
60K *wd = 5 nights at a class 3 hotel and 50K airline miles. (WOW)

Starwood gets you hotel stays, a 1.25 per point conversion to airlines, and even the possibility of redeeming on Hilton.

DC will let you move them to *wd too but at a .6 per $ rate. (If you frequent BA, that DC deal of 2 points per $ may just be worth it.)

One possible downside is if you attempt to charge the total amount in one lump sum beware of your credit limit. I think Amex is stingy with the amount they initially give. I used the Green card for mine once but Amex wanted to make sure that I had the money before they would allow the transaction.

my 2c
BSL