The Witchfire Trilogy (adventure modules), The Monsternomicon, and Lock and Load: The IK Character Primer are all excellent books.
As soon as I can find/start a group locally, it will probably be the first thing I run.
The company site isn't too bad and have downloads of character sheets, maps, fiction, and other items that gives additional setting flavor.
They do miss targeted release dates, however, the quality of the product is certainly worth the wait.
Besides firearms, steamjacks, and mechanika, there are three additional character races and variations of standard races of the PHB (though halflings, half-orcs, and gnomes are omitted). The take on religion is nicely done. With the character primer human ethnicities come into play with varying advantages/disads.
No, I don't work for Privateer Press (but it would be nice

). But I have enjoyed the products they have produced so far and definitely recommend them.