Note: Will refer to this book as APAP in this review. Also this will describe how I've been using the book, to give you some idea of it's flexibility.
Mechanics: Uses the Heresy System, created for the Victoriana RPG. When you are making a test you roll a number of d6 equal to their Attribute + Skill. Every 1 and every 6 they roll is a success, with a roll of a 6 exploding. An average test requires two successes to be considered successful. The more successes achieved, the greater the success.
Complications are added in the form of Black Dice, which represent adverse or difficult circumstances. These are rolled as part of the dice pool, but for every 1 or 6 rolled on a Black Die, a regular success is negated.
It creates a very player driven game, as a DM you really only need to roll for contested items, like combat so you can focus on the narrative -- which I've found very important in the system. To give players a feel of the 'universe' and to give them time to react, describing the scenes around them is very important.
A note on Black Dice, incidentally, I've found using them exclusively for aspects of difficulty outside player control is the best way to use them -- using them too much seems to give the impression you're 'picking' on the party. Environmental things, e.g. 'Your Airship is fighting another one in a storm, all handling and gunnery rolls have 2 Black Dice or perhaps 3, as the ship is rocking and shuddering in the high winds and lashing rain.'
Setting: The setting speaks for itself honestly. Steampunk. Airships. Fighting tyranny with piracy! I personally use this to supplement my Victoriana 3rd Edition game, with it's airship rules. So, you can "co-mingle" the systems rather easily.
The books setting itself is both brilliant, and at the same time incredibly cheesy - Which may or may not be your cup of tea. From the name of the main antagonist, to other aspects of the setting make this more lighthearted than Victoriana is - it's good fun if you want a more over the top swashbuckling adventure. For your more hardcore RPG fans, who want a serious game, you might want to consider tweaking some of the setting information -- which is why I've used the Victoriana 3rd edition's Crimean War as a backdrop/catalyst nations developing new engines and airships for combat. And so use the airship rules to supplement the game. The flexibility and cross-over of skills means the two books can compliment each other very well.
Essentially, I think it's a really good buy if you want to play a steampunk setting with an emphasis on sky-boats!
Summary: I think it lacks the depth, of a truly hardcore RPG setting, which is really the only thing stopping me from giving it 5 Stars. In combination with Victoriana, which is really the best thing to compare it to, you can create some absolutely fantastic games. But alone, it's a fun entertaining, swashbuckling adventure through the skies.
It stands up on it's own by offering an alternative "future", the Caribbean of the Skies. A dystopian Empire to contend with, whilst your crew bravely uphold their cunning ruse to trade in 'legitimate ports' before making a run with their black market cargo to High Tortuga. Cannons. Swordplay. Stupidly named Airships, because your RP group are all Manchilds. Bargain.
[4 of 5 Stars!]