Comparing Siblings

[Archy]

Recently, I've been flipping through catalog pages and need peoples' opinions.

Would you prefer a horse (weanling or yearling) who's family has produced one stakes winner by a good sire and a few to no other winner OR A horse who's family has produced all winner by an unknown winner (with 5- to 6- figure earnings), who is now bred to a good sire (basically stepping the mare up)?

Let me add that it would be a purchase to race with an option to sell.