| MrCharisma |
Personally I'd go Draconic. The energy damage from claws is a little more customizable, and you can get some of that bonus STR back by taking 4 levels of Dragon disciple.
The main draw for Demonic that I see is Demonic Bulk if you're playing an outsider race (tiefling/aasimar/etc) who isn't a valid target for Enlarge Person.
Also I guess it depends what level you're planning on playing.
EDIT: Part of thisbdecision is that I like the bonus feats for Draconic better. Really either one is fine, so whichever one you make you'll enjoy it.
| deuxhero |
The claws on both are meh, especially if you aren't going for a natural attack build. Trade them for a bloodline familiar. Both bloodlines have fairly useless extras on their familiars for the most part (your familiar likely has unlimited flight and won't be making natural attacks) but (improved) familiars on their own are great for a charisma based (UMD) full HD full BAB class with decent skills per level.
Dragon's breath weapon is pretty meh. Demonic Aura isn't great (few things without fire resistance 20 by level 16) but is no action damage. Draconic has a better capstone, but very few builds will get that far. Dragon's form of dragon II is nice, but only if you focused on natural attacks (which this bloodline barely supports) and redundant flight.
Both have enough staples in their bonus feats for it to be a wash. Spells are a wash: Fly, Bull's Strength, Rage and Fear (2 each) are all pretty meh (since Fly and Rage won't stack with bloodrage).
In the end both the Flight and Enlarge parts are easily duplicated with magic or magic items. I'd have to go with Abyssal since the further boosts to strength aren't easily duplicated