Ok…you guys knew I would chime in. 
@sgarman
The IK is, without a doubt, the best on the market right now. I’ve tested everything I could get my hands on, but very few come close. Also, understand, the IK was co-developed with Leslie. Maybe someday, neural networks will be applied to a Leslie, as they are doing with current amp sims…truly realistic.
There are a few differences between the IK’s. I prefer the Amplitube version. The parameters are close to the same, so really subtle differences. The TRacks version is more user friendly. I explored all this on my VST Organ thread. https://community.cantabilesoftware.com/t/corky-s-vst-organ-tips-and-tweaks-page/