Currently, I have miles with United, AA, and US. It seems like the low hanging fruit available is with Delta, as I can easily get 30K miles with a credit card of only 1K of spend.

However, I do not even know if it is worth it for me to do it. The program seems to have some value since I can redeem one-way flights, but I am really having a difficult time seeing how to actually get the reward tickets at a reduced rate (the low tier amounts)

Most likely, the 30K miles would go towards a trip to Europe.

Should I even bother with Delta?