Lee,
I've tried both. I chronographed the Speer SP, Hornady Sp, and Sierra SP (all 130gr) but with N160... ending up at 55.0grs at 2960FPS. All at the same trial session, and there was no difference in MV's between the different bullets. They need different seating depths because their ogives vary (the Speer was the 'bluntest' so needed to be seated deepest). The Sierra was the most accurate, but the others weren't far behind.
I've seen N560 shot in a .25/06 and .270, and it's lively with a pronounced muzzle flash. I wasn't the only one to notice this... some remarked what a good flame thrower the rifle was.
That's all I know...