Whoa! I'm not trying to start an argument here. The OP asked about effectiveness of the fence- I responded. I've owned it for 15 years and had multiple breeds!
And a GSD is NOTORIOUSLY responsive to training. That's why they are K-9, battle, bomb-sniffing guarding wonders! You can't say they are not responsive to training because quite frankly they are! They are hard-wired for it!
I've had 3 Basenji's- they are the total polar OPPOSITE of GSD's! Hard headed, independent, strong prey drive etc.. and they were totally fine with the invisible fence!
GSD's
Often used as working dogs, German Shepherds are courageous, keen, alert and fearless. Cheerful, obedient and eager to learn. Tranquil, confident, serious and clever. GSDs are extremely faithful, and brave. They will not think twice about giving their lives for their human pack. They have a high learning ability. German Shepherds love to be close to their families, but can be wary of strangers. This breed needs his people and should not be left isolated for long periods of time. They only bark when they feel it is necessary. Often used as police dogs, the German Shepherd has a very strong protective instinct, and is extremely loyal to its handler
Basenji'sTemperament
Basenjis have a strong prey drive. According to the book The Intelligence of Dogs, they are the second least trainable dog. However, Basenjis are extremely intelligent and respond to training that is consistent and positive with plenty of treats. Basenjis do not respond well to punishment, such as yelling and hitting, which can cause them to utter a warning growl.
http://en.wikipedia.org/wiki/The_Intelligence_of_Dogs
GSD's are in the top 3 as far as trainability. Basenji's are in the bottom 3!