MFitz,
Based on my research, there really are only 2 "engines" for the consumer models even though they have many different labels.
There's the traditional, tried and true model 5200 with the V0103 motor. This same motor is in the following machines: CIA™ Professional Series®, Creations® II, Creations® GC, Professional Series® 200, Total Nutrition Center, 6000, 6300, and Pro500. QVC sells the Creations line of blenders which are the same as the flagship 5200 model. The difference in the Creations line from QVC is that it comes with a 5-year warranty instead of the 7-year warranty.
Then, there's the Next Generation line of Vitamix with a little more powerful motor, wider and shorter container, and supposedly a little quieter during operation. These include the Vitamix 750, 7500, Pro 300, and the Creations Elite.
So, don't let all the "badges" on the Vitamix confuse you, underneath many of them are the same engine.
Hope this helps.