Update: Decided to go with Chase Freedom Unlimited

I decided to go with Chase Freedom Unlimited over Chase Amazon or Discover.  Chase Freedom Unlimited seems to have the benefits of both plus a $150 sign-up bonus when you spend $500 within the first three months (seems pretty generous).  Once I was approved for CFU, I went ahead and closed my legacy BoA AMEX, as I have little use for it anymore.  Don't worry, my CFU initial credit limit is quadruple the credit limit I had on the BoA AMEX, so zero negative impact from closing the account.  I'll probably garden for a while, but if I go for one more card in the near future, it will probably be the Discover.