The green dice has 70% success sides, 30% boon sides, 20% delay sides.
The red dice has 50% success sides, 30% boon sides, 20% fatigue sides, 20% bane sides.
Why would anyone EVER use red dice? When looking at action cards they don't even warrant the extra risk. When you do the math the green dice will always have a greater chance of creating three successes. The green dice only have 20% chance for a delay, which isn't that serious. The red dice have 40% chance for something nasty, especially the cancelling of boons for criticals.
The game works pretty well generally when characters have stats at 4 or below... but from there is starts to go wrong. I don't see a reason for skill checks when a stating character has 85% chance of making an average skill check and 58% chance to make the hardest check. Soon rolling won't matter unless the GM make everything difficulty d4 and cheats and invents difficulty d5-10.
Opposed rolls. Sneaking past someone being alert. It is tipped way too much in favor of the one making the roll. If you sneak past someone you are almost certain of success... but if the guard decides to make an observation roll he's almost certain to discover the PC. It works both ways and I can see rolls becomming increasingly pointless.
I really think they failed on the dice. There are WAY too many successes on each die to make a balanced system. Some rolls are d0 and even with ONE die your chance of success is 50%. There should be perhaps 2 success symbols on a blue die instead... but alas, I think they were caught up in the fancyness of the system to bother with maths. Since the system doesn't use regular dice it's not that easy to change around. But I am thinking about using regular dice and setting a success number, like in the Vampire system... that worked.
It would be nice if FFG could comment on this, the success rates and these dice mechanics.
IMO they should just redo the dice and make a mathematically balanced system.