[pvidler]

Just from the descriptions and photos, it looks like the mini will be breadboardable.

The bigger one almost certainly not -- it's arduino compatible and the gap on one side is visibly smaller than the other. Also, it's not clear if the big one will have pins dropping down below the board (just looks like female headers).

[mtdev]

Yep, I just looked at the pinouts on the larger one and its very likely that they kept the same out-of-spec spacing as the Arduino Uno.