My opinion based on what I read here on bang.cz.
Mick Defender - Seems fine. I don't like the name though.
Evalin the Bang - I like the idea, but I think the ability is more powerful than it might seem at first sight. I should play her. And I don't like the name.
Henry Block - Seems fine.
Lemonade Jim - Seems fine. But I don't like the fact that, just as many other abilities, it becomes useless during the final duel (an intelligent opponent will discard his Beers, instead of using them).
Colorado Bill - Does his ability apply to Missed! provided by Barrels or Jourdonnais's ability? If yes, I don't like him. If no, it's fine.
Escape - Like it. It's nice to have some defense against cards other than attacks.
Last Beer - Don't like it. The idea and the name is lame, and it prolongs the length of the final duel. Moreover, once you add the equipments from Gold Rush, the final duel is really going to last forever.
Tornado - Don't like it. It destroys your hand and gives your cards to another player with no advice nor defense. The only other card that does something similar is Rag Time.
Backfire - I don't like it. It makes the game much more random.
Tomahawk - I don't like it. Another free BANG! per turn and at a decent distance. There's a reason similar cards have a distance limitation of 1.
Aiming - I don't like it. More BANG! per turn.
Faining - Two more BANG! per turn... Hate it.
Saved! - Finally a defensive card. Still, it makes you steal cards from a helpless ally: WTF?
Lemat - Like it.
Shotgun - Like that player already isn't in a bad situation?
Bounty - I like it, but there's already a Bounty card in Gold Rush.
Rattlesnake - Moooore random attacks.
Ghost - Nice, but it makes the Renegade's life a real nightmare. I think the ghost shouldn't be counted among living players.
Overall, I think this expansion has some real balance issues. Almost all the cards are offensive ones: and very offensive! That will weaken defensive characters and defensive roles, overall making the Outlaws' life much more easier. I can imagine it: the Sheriff shoots at an Outlaw, he plays Backfire and the Sheriff loses a life point...
And it increases randomness. Where's even the point in planning how to attack with that precious Volcanic, when there are so many BANG! that don't count against the limit of one BANG! per turn?