A friend of mine and me recently got into a discussion regarding Black Crusade after having an initial look at the rules. We haven't looked at them in depth yet however he raised the point that mortals get 500xp more than Astrates but that doesn't really cover all the bonuses that Astrates get from being space marines with all those lovely implants. I countered that they seem to get a few more talents and skills in character creation. Thats ok in the short term but chaos space marines will always have a higher class of weapons available to them in the legion weapons. The special abilities of the mortal classes seem slightly better but the chaos space marines effectively have +5 to all stats.
I ask those who have been reading the book for longer and those who have been lucky enough to play the game a bit in the long run do the mortals just have to tough it out and just be lagging behind a little or do they gain some other advantages, not necessarily combat ones, which add to what they bring to the party. Obviously the mortal characters have an advantage in most social infiltration adventures however I spotted the Illusion of Normality gift which can let even a horribly mutated chaos space marine walk around on a shrine world... in theory atleast.