I've done lots of research - no worries.
Plus I told my breeder that considering she'll be my first GSD, I want a dog that doesn't have too-crazy drive. I've talked to a few people who have dogs from her and they're all beyond thrilled.
I was watching some videos of a Sieger show, and it was depressing watching some of the dogs scurry off the field when the helper would advance toward the dog at all. Not the kind of dog I'm looking for. I'd rather have a dog bred for temperament and working ability than looks, anyway.
I've also had the opportunity to see a GSL do flyball - it looked awkward racing compared to WLs.