I'm not writing to discuss any single card, but rather one aspect of how to
consider the value of any single card.
Consider the following...


My card can put the active pokemon to sleep...
  Well, that's nice but the defending pokemon isn't in much danger of taking
additional damage, AND your opponent gets to attempt a wake-up at the end of
the very turn you put their pokemon to sleep.  That's even before they need
to attack.  That's a fifty-fifty chance that your attack was even successful,
and if it was, there's only a fifty-fifty chance that your opponent will be
incapacitated for more than a single turn.


My card can paralyze the active pokemon...
  Not bad.  Unless a trainer card is employed you don't have to worry about
attack or retreat next turn.  Though they can still attach energies.  And it
only lasts one turn.


My card can confuse the active pokemon...
  Fun.  Except for the trainer card possibility, your opponent is faced with
a hard choice.  Try and attack, risking 20 damage.  Or try and retreat,
risking the loss of energy for no real gain.  Especially if the confused
pokemon's attacks require a coin-flip to be successful.  Think about it...
instead of flipping one coin for Farfetch'd's Leek Slap, your opponent now
has to get two consequtive heads!


My card can poison the active pokemon...
  The only status ailment that can be combined with another.  The only status
ailment that MANDATES damage to the pokemon at the end of EVERY turn.  It
doesn't keep the opponent from attacking you but unless they've got scads of
Hit Points, the pokemon isn't likely to remain active for long!



So, if two cards are equal in all other respects, I generally use the
following to order (best to worst) to determine which card is better;


Poison? Best bet!
Confusion? How can it go wrong?!
Paralyze? ...not bad.
Sleep? ZZzzzzzzzz....