BIAS Desktop is the world’s most accurate, thorough and versatile guitar-amp modeler and designer. Its advanced amp-modeling engine captures the warmth and feel of real tube amps in every aspect, component by component. To start, the plug-in includes 36 authentic models of the most sought-after vintage and modern amps in rock ‘n’ roll history.
This alone is worth it—BIAS is my favorite amp modeling software for iOS, but then they added this to the Mac version:
Amp Matching utilizes a collection of underlying technologies to analyze and compare your currently selected BIAS amp model and the sound of a target tube amplifier, the corresponding cabinet and the microphone in front of it. It then executes the tonal compensation and enhancement needed to make your amp model accurately match the target tube amplifier.