Yes. Yes it is.
For twenty-six issues (and a zero issue), writers Justin Gray and Jimmy Palmiotti have teamed with artist Moritat to produce the most consistently entertaining, high-quality book that DC Comics is putting out (and yes, I mean it's better than Batman).
While other New 52 titles have had their ups and downs, struggling to establish the new versions of their heroes in this rebooted world, Palmiotti and gray have rolled with everything thrown their way, while still writing the same Jonah Hex we loved pre-New 52. Whether it's tying Jonah to old Gotham or having him time travel and visit modern Metropolis, the stories are always fun and the spirit of the character never wavers.
DC does this book a great disservice by putting no marketing money behind it and charging a $3.99 cover price. If they dropped the book to $2.99 and made half an effort to tell people about it, ASW would be a 'Top 50' book every month. Thankfully, Palmiotti, Gray and Moritat never let that affect the fantastic stories they're telling every month.
Not reading All-Star Western? I feel bad for you, but you can remedy that right away by picking up the trades, or the entire run digitally.
Do it. Now.