Under the best of circumstances, sire lines are nebulous things. They come and go. They seem almost as thin and vaporous as clouds. Just think how the Bold Ruler line, or his sire Nasrullah’s line, has risen in visibility and important, then departed from sight and reappeared again like a friendly ghost.
So let’s not make too much of the “line” part. In a rational sense, it all comes down to the individual, and certainly one of the individuals who has made the Storm Cat line is Giant’s Causeway.
When we think of sons of Storm Cat, Giant’s Causeway is the one. Both as racehorse and sire, Giant’s Causeway is a massive presence in the résumé of his famous sire – a bit ironic because the chestnut champion is distinct from Storm Cat in many ways.
Certainly as a sire of international import, Giant’s Causeway is the most recognizable and most successful of the many sons of Storm Cat at stud, but the lead sire for Coolmore’s Ashford Stud is atypical from many other sons of Storm Cat by siring a large percentage of horses who prefer a distance and show their best form with maturity.
Those are admirable traits, even if they diverge somewhat from the “typical” Storm Cat tendencies of speed and early maturity. The salient quality about Giant’s Causeway stock is class, and from nine crops now age 3 or older, he has 129 stakes winners. What puts him at the top of the list of leading American sires in 2012 is stakes performance and especially graded stakes winners. To date, he has 62 graded or group stakes winners around the world.
And just like his sire, Giant’s Causeway was a success from his first crop. That group included classic winners Shamardal and Footstepsinthesand, and both have sired high-class performers in their own right.
They are also important for the perception of Giant’s Causeway as a sire of sires, the test that separates very good sires from the great ones. Both were from the year Giant’s Causeway stood in Ireland, and from his American crops, he has several young stallions, including Claiborne sire First Samurai, who last year had G1 winner Executiveprivilege, a finalist in Eclipse Award voting as leading juvenile filly of 2012.
As expected, then, Giant’s Causeway is also greatly preferred at the sales, and at Keeneland January, he is covering sire of five mares (Hips 141, 333, 605, 749, and 753), has a half-dozen daughters entered (Hips 90, 224, 302, 317, 373, and 568), and is the sire of a single short yearling (Hip 213).
bloodstock in the bluegrass 
And not to forget Frost Giant who’s first crop to the races was excellent by almost any standard.
Just look at Fedbiz!