I recently discovered that the opponent against whom I typically play X-Wing was completely unaware that attack dice are more likely to hit than defense dice are to evade.
On the 8-sided attack dice, there are 3 hits + 1 crit + 2 focus + 2 blank sides, so you have a 50% chance of hit or crit before focus.
On the 8-sided dfense dice, there are 3 evades + 2 focus + 3 blank sides, so you have a 37.5% chance of rolling and evade before focus.
This means that 3 attack dice vs 2 defense dice is better offensively than 2 attack dice vs 3 defense dice is defensively, and is a contributing factor in why Stealth Device seems to be disappointing for many people (my gaming partner included, which is how I discovered that he didn't know this in the first place). This could also be interpreted to mean that focus is more "valuable" on defense because evades are more rare, but I think it is a stretch to make this claim.
Anyway, just wanted to throw that information out there in case anyone else had somehow missed it.