Auldey L3 or K2J warning line

are these good and wich is better

If you asking “are they good?”, yes, they are great.

But “which one is the best?”, that would be back to your prefrence.

Both are around same diameter.
On the string, the L3 is lighter and faster, while the warning line is heavyer and little bit more stable.

The shape is alse diffrent.

I would say go for one you like, and based on your play style.
If you like play fast, L3 might be good, otherwise, warning line,

Hope this help.