I think (not
@Lain but watching football so I'll chime in) it really depends on what your points/miles goals are for the near and/or distant future.
If you have goals requiring Starriott points soon then I'd keep using the SPG Biz. If you don't, then stockpile the MRs--they are so much more flexible and the transfer bonuses that occur every so often can make them even more so. We just sockdrawered the SPG Biz after using it for gas for the 10% discount over the past several months---if that (or something else) returns then I'll be pulling it back out. Now back to using my Gold Biz for 3x on gas...unless a better amex offer comes along.
And happy dance for me today...noodling around searching for the
Amazon amex offer (which I still don't have on 5 AU cards, 5 personal cards and 5 biz cards

) but under "featured offers" I had the enroll in Pay Over Time Enrollment for another 10,000 MRs. Whoo hoo

-- what's better than 2,000 for spend...free 10,000 MRs!