Originally Posted by
salsa
You will be much better off getting out of SkyMiles and putting your spend on Chase Ultimate Rewards or Amex membership rewards and even Citi cards. That is especially true if you aren't earning Delta elite status through flying. Those other programs and points are much more valuable and can be used in a variety of programs. Plus those cards have better travel benefits like Priority Pass lounge membership or Amex Centurion Lounge membership. Amex Platinum cards include SkyClub access.
This. Transferable points are your friend.
That said, you may still need some more Delta miles to redeem your existing ones for where you want to travel, so still keep an eye out for decent sign up bonuses on DL cards. 30k miles is absolutely not worth burning your once-in-a-lifetime Amex welcome bonus over, so hold out for better offers.