Main Gauche, to sum it up, if you liked Zweihander, it's more of the same.

If you don't like Zweihander, it's more of the same.

If you found the weird constant pop culture references funny in a kinda Tommy Wiseua's The Room sorta way and the waffling maddening in Zweihander, it's more of that.

I actually found myself laughing at the material (not with it), the waffling frustrating and everything else just totally fine.

Zwiehander is AWESOME. Main Gauche is NOT. The biggest weaknesses of the core rules are:

1. The Fluff that separates over-lapping classes.
2. Weapons (seriously weird selection) Main Gauche doubles down on these weaknesses, HARD. Many of the professions are way out of step with the tone of the setting, many other professions present ludicrously racially specific fluff which again, just doesn't fit with the tone at all. The expanded weapon selections are just weird and off-putting. Please explain to me how exactly Claymores and Great-Swords don't qualify as Zweihanders from the core book? Or how about the plethora of pole-arms that are introduced to a core system which extensively mocked AD&D's obsession with different types of polearms, to the point of stating that "people engage in Gygaxian musings" about different sorts of pike? On top of this, Main Gauche goes way out of it's way to include a bunch of special "not-magic abilities" and "not-magic materials" to a low-fantasy setting which just come across as irritating.

This isn't the worst possible add-on to the system but everything it accomplishes could be better handled with house rules that don't make it impossible to avoid the fact that Zwiehander as a whole is a direct rip-off of Warhammer Fantasy (seriously, Blitzballers? WTF, does GPG want to get sued by GDubs?)

This book adds a ton of options and provides useful tools. I recommend it!

So far I only skimmed, it but from the look of it: new profession, news skills, new spells and new rules. So far so good, nothing new... wait, this all stuff is crazy. I never knew I needed zeppelins and steampunk motorcycles in my dark fantasy gaming, but I did.

This supplement has well thought out stuff that's not obvious to have, and this is it's best selling point - this stuff is fresh

An awesome expansion on an already awesome game. Massive character classes/weapons/vehicles additions. I would say the most interesting is how "Daemon's" can be accepted as your god of choice, and gain powers in return by doing their bidding. "You want to RP a chaotic and evil villain? that's fine, we'll throw in some incentives as well!". Also the community for G&P are very helpful for any questions that may arise at any point.