It sounds like there are a lot of similarities to the systems, but it's the differences that are the killers. So it looks like I'm going to have to read through the rules to get a good handle on this.
Beyond the core rules, are there certain books that contain critical new character creation mechanics? Using Changeling as an example, the concept of dual kiths introduced a whole new set of complexities that needed to be handled, and those weren't outlined in the core rulebook.
Thanks!
This may be a little old but if you have any questions, I run a nWoD game (with VtR, MtA, & WtF characters) and play in a Scion game so pretty familiar with both.
The "Main" difference in the games are how dice rolls count and combat/initiative but that wouldn't affect HeroLab much.
The main character creation difference are "Epic Dots". So for all the Attributes (same ones as in WoD), you get a "Square". Lets say you have 4 "Dots" in Strength and 3 "Squares" or "Epic Dots" in Strength, and you have 2 dots in Brawl, to attack you would roll 6 Dice (the dots) and then add in 4 "automatic successes" to that roll for your epic dots in Strength. (you get +1,2,4,7, etc for 1,2,3,4 etc epic dots, it's not a straight progression).
And for every "Epic Dot" you take, you get a free "knack", so that would be pretty close to "Disciplines" in VtR (3 dots in Auspex really nets you 3 different powers, but in Scion you get to pick your knacks from a pool).
Otherwise, creating Scion, IMO, would be REALLY easy (outside of adding Epic Attribute squares and tracking health slightly different). There are FIVE books TOTAL. And none really add anything "new" or "different", just the powers get more and more godly. You have Hero (character legend ratings or "levels" 1-4), Demi-God (rating 5-8) and God (9+). Ragnarock just adds a few more Knacks/Boons to pick from, and the Companion just adds more Patheons and so really just more Knacks/Boons.
As far as game systems go, this has to be one of the cheapest games to get into. I believe WW pretty much said this is all they are doing book wise, so once you buy 5 books, you are done (and you can skip Ragnarock as that is a side campaign really) and you don't really need Companion either.