I am no veteran on the CC churning (that's for sure), not even really a 'churner'.

However, I can tell you the AMEX SPG card is a worthwhile card to think about keeping.
The points transfer to many airlines on a 1:1 ratio (making the card worthwhile for the annual fee).

This was my only card for the last many years. I would not want to part with it, and I have read many veterans post that this is 'their go to card' as well.

Just a thought.