It's hard to say if -30 Flee is bad for you or not. I mean, if you had 1000 Flee already, then -30 is no big deal. If you only had 100 Flee then -30 becomes a problem.
(Note: the numbers aren't realistic, just an example to make the math easy for you to see)
Another note to think about is whether your character's build based around absorbing hits or avoiding them. If your other gear is chosen primarily to buff your defense, then the extra 150 defense points is a great choice and the loss of Flee isn't bad. But if your gear is mostly centered around giving you more Flee to avoid getting hit altogether, then -30 Flee is a bad choice for the setup you have.
Whether the card is good for you isn't something people can give you a good answer for without knowing the rest of the story. Make sense?