How balanced are the character powers in Colt Express?
If one compare the base power, we can easily conclude that Ghost and Doc got the easiest to use powers, since it works no matter what. Belle has an interesting power that needs someone close, Cheyenne Django and Tuco changes how a basic card is played. Cheyenne is, statistically, the one with the "hardest" to use power, since it only works for one card in her deck AND only for a type of loot.

Belle's power is usually considered powerful, because it makes her hardest to hit, on average, with a lot of players. On 3-4 players game, her power is harder to use, but this power can save you and punish your opponents, paving your way for success.

Ghost's power is psychological warfare at it's finest. It works for every round, it hides the first card of each round... On a game where you try to predict opponent's move, it's horrible to face. The power doesn't help you "win" by itself, with bad hands it can also do nothing, but the bluffing abilities of this power is incredible - if you can pick your character and dislike mind games, pick him, facing him is not for the fait of hearts.

Doc's power is bland. You draw one more card. Every turn. That's boring, but practical. You'll more often than not get the card you need and not be too crippled by bullet but that's it. Your opponents won't see you play differently, because you won't. You have no specific strength, no trick, it's just the cards and their stated effect. Surprisingly effective, he's never a bad choice and id perhaps the easiest character to play.

All in all, I think Ghost is the best, but depends on your group and how well you can bluff. With very large groups, I tend to go for Belle, because her power is much easier to trigger and well, it helps. Doc is the one I pick if I know people won't buy bluffs and are prone to mass shootings.

With one of the expansion pack, there is a chinese kung fu girl available which can move horizontally and vertically on the same move (well it's a bit more complex actually). She's VERY good because of this, her movements are hard to predict, and a skilled player always get where he wants, faster than anyone else. If expansions pack are included I'd vote for her.