At this highest end of the blender market there is no rational basis for choosing more power, they're all so much way beyond adequate.
Vitamix model numbers are confusing. The same base with different pitchers gets different model numbers. The same base with the same pitchers and different cookbooks gets different model numbers.
The new top of the line highest priced Vitamix blenders includes a "soup" cycle. Other new, "higher end" Vitamix have some "pre-programmed" cycles. In a word, these are useless. Forget about the 500 series.
FWIW, the old 5200 "Classic" series blenders can be found here. Also look at the identical "Professional CIA," "Professional 200," and "Professional 300" designations. A Professional CIA is a 5200 which is a Professional 200. The differences are cosmetic and packaging. For instance, the CIA has a slightly larger dial, a choice of colors, and a different cookbook.
Blenders with the old packaging can be found at a substantial discount if you search the web. If price matters, look around. Don't settle for Vitamix or Amazon. Through a series of adventures and misadventures -- not to mention my professional discount -- we ended up paying $300 at Sur La Table for a brand new, stainless, "CIA" model which Vitamix still lists at $529.
While I doubt you'll be that lucky, you should be able to find a new, similar Vitamix for ~$400. For instance, QVC has the "Creations" Vitamix for $439, not to mention the Blendtec Total 90 for $375. But, KaTom has the Vita Prep 1002 (Vitamix's actual professional "Professional 200," but with different feet, no cookbook, and available in a choice of "any color so long as it is black") for $376. Aaaaaaaaaaaaaand just in case "ridiculously over-powered" isn't enough because you want to mill flour for your family, your neighborhood, all of your acquaintances, and most of your geographical region KaTom also has the "beyond ridiculously over-powered" Vita Prep 1005 for $482.
In case you're not already super-confused, consider the Waring XTX 1200 for $350 from BlenderPlace.com. Why not? It will do everything the Vitamixes and Blendtecs can, and for the same price.
My understanding is that Vitamix's new, square, low-profile, 64 oz jar, has a better "vortex" and out performs the older taller jar for a few tasks, like milkshakes. It should, as Vitamix copied it from Blendtec and ended up losing more than $20 million for patent infringement. Is it better enough to pay [gasp] retail? I doubt it. If you want the square pitcher forsake the variable speed, offend Vitamix and buy a Blendtec. (Apologies to Shakespeare and Waring.)
If you've decided that nothing less than a Vitamix, Blendtec, or other super-powered, super expensive blender will do, and frequently use your blender to puree a lot of hot food, I recommend Vitamix or Waring for their variable speed controls which allow slow starts, and especially Vitamix (and Vita-Prep) for the vented pitcher caps.
Otherwise, if you're still undecided spend a few hours looking for the best prices and buy on that basis and on appearance. There's no valid reason to allow the choice to become an obsession. At the end of the day, they're just blenders. In the $350 - $375 range, the Vita Prep 1002, Waring XTX 1200, and Blendtec Total 90 Total look equally attractive.
Edited by boar_d_laze - 9/15/12 at 6:47pm