not sure if this is right. Everyone I know who went thru seedcamp said the #1 benefit was the connections [which you'd get via YC] and #2 benefit was so far from #1 it wasn't worth mentioning.
I think seedcamp is more interested in later businesses - maybe about 3 months post launch. When they have traction and the proposition is more refined. My understanding of YC is that they love to get down and dirty in refining that proposition. Hence YC being more risky, hence the more deals.