The Jagdpanther is one of the most famous German tank destroyers of WW2. Even though it was built on the chassis of the medium Panther tank, it's classified as a heavy tank destroyer. Many consider it the best German tank destroyer. The Jagdpanther combined good mobility, high protection, a powerful gun, and it had defensive armament, which is important for a tank destroyer. However, its influence is often overestimated. The vehicle was only available in large numbers by late 1944 and arrived on the Eastern Front only in January of 1945. The way these tank destroyers were used was often different from the original intention and this impacted its usefulness. Finally, the vehicle was far from the most reliable.
An alternative to Waffentragers
Initially, German tank destroyers followed the concept of the Waffentrager, vehicles with either bulletproof or thin anti-shell armour. This applied even to vehicles with powerful armament, including bunker busters that were supposed to destroy defensive fortifications. These included the Pz.Sfl.IVa on the Pz.Kpfw.IV medium tank chassis and the Pz.Sfl.V on the chassis of the prospective VK 30.01 heavy tank. Ironically, these bunker busters never faced off against the Maginot line or any other fortifications. They were used as tank destroyers and ended their days at Stalingrad.