I think Grey Wizard is the worst, except for maybe, and I'm sure someone has an amazing deck using him,
Bearer of Obligation. Granted he is a ring-bearer, but I don't like how almost every other RB companion can do something even if they aren't the ring-bearer except this one. I guess Faramir doesn't, but he does have an ability.
The Grey Wizard-Choke, and
Trust Me potential***Possibly Worst Gandalf
Friend of the Shirefolk-Rainbow potential, hunters potential, High Strength
The Grey Pilgrim-Splash, draws cards, Aragorn Signet
The White Wizard-Gandalf Signet for
Trust Me and strength but does require 3 twilight, good
in twilight flood decks***possibly worst Gandalf
Greyhame-Discarding Hobbits, but Theoden signet***Possibly Worst Gandalf
Mithrandir-Aragorn Signet can help him heal, High Strength, damage +1,
shadowfax can help, as can
sent backDefender of the West-Good for a single or 2 culture deck, high strength, Gandalf Signet
Manager of Wizards-Elven Telepathy, -3 to minions, can lose intiative
Leader of Men-Start Gandalf for 2 twilight, allows for Gandalf to help other cultures with his tech, but limits his skirmishing power
Leader of the Company-Another Gandalf that helps Rainbow decks and can splash also, resist.
The White Rider-Skirmishing potential, I'd like to see a deck using him, Skirmish canceling if nothing else
Bearer of Obligation-see above. ***possibly worst gandalf, but after having listed some of the ones above could be worse
Powerful Guide-8 str., works with hobbits, direct wounding, draws cards
Returned-Gets his sword, reinforces tokens
Wise Guide-8 str., and can cancel events
Sorry if i missed any.
I'm thinking probably
Greyhame,
the White Wizard is not really my favorite either, I think
Defender of the West is a more Reliable version of him. Then there's
Bearer of Obligation. Again he doesn't do anything if he's not the Ring-Bearer, he is even worse because he is 5 resistance.
For me, I think
the Grey Wizard is better than all of those, with possibly the exception of
Bearer of Obligation because I'm not really familiar with decks that run Gandalf as the ring-bearer.