Typically they're not worth it, ESPECIALLY if you never play the Premium/LE. MET is the biggest example of this. Deadpool, you play $1700 for a diverter and some (Yay!) drop targets.
Some though play completely different, like BKSOR (still kind of stinks), and GOT. Those are definite premium pins for me.
Maiden Premium/LE literally has nothing but crappy, headache mechs added to the game. Definitely not worth it.