Roland's ability, the card!
Grete Wagner is super expensive, so not an autotake by any means, but the ability to turn killed enemies into clues is brilliant, if you have a powerful cash engine (such as by adding Stand Together and Clean Them Out) then you can run Grete plus a good weapon and not be completely broke, at which point you should be able to munch through enemies and rack up clues with her.
It's a brilliant Roland Banks card, it directly synergizes with his shtick. It's a great Mark Harrigan card, as the damage she takes is a card for Mark, All the characters really can use her, but I would like to say that she stands out perhaps exceptionally in a deck that has powerful economy to start with (Zoey, Leo, Tommy, where there is enough resources rolling around to pay for both her and the weapon of choice as fast as possible, Grete is useless if you cannot win fights!
Grete Wagner upgraded is also very good, especially for a Roland where the + is useful and the ranged-cluegetting synergizes with his base ability to become hyper-efficient at turning beaten enemies into clues.
Be aware that, like Roland Banks, the ability specifies that -you- must defeat the enemy to net the benefits.
Grete Wagner is good, but be careful about your resource economy.