Just got this. IMO it's too pricey for such small deck of cards, & of course all 7 Wonders games are expensive for such low-quality cards (with beautiful pictures). I've been spending even more $ to sleeve the cards, but nevertheless, 7 Wonders is a great game.
These double-sided boards increase the game's longevity. Both English & German versions are identical & language independent. The translated English instructions are poorly written, but you can get help from the geeks here. I've retyped the rules & now they make sense. YOU CAN APPLY THE CHALLENGING VARIANT TO ONLY THE NEW BOARDS.
The original rules can be used with these boards alone or the mixture of old & new ones.
Despite its clumsy translated instructions (there's plenty of helpful clarification from the geeks here), I wouldn't play SA w/o it. It makes the game more strategic. A 4-person play keeps the game within 2 hours. It might not better than the base game but it's fun & gives variety!