How important is RPM in a blender? I'm looking at getting a new blender, basically the main things I want to be able to do with it are make curry pastes, ultra smooth restaurant quality purees and soups and grind small amounts of spices (I'm talking 1-2 teaspoons). This leaves me with two choices (possibly three of which I'll get too): the Blentec or the Vitamix. The former goes to 27,000rpm and the latter goes to 37,000. I'm wondering is there much of a difference once you get up to crazy speeds like that. 

The other option is a Thermomix, which from my reading only hits speeds of 11,000rpm. Unfortunately, given that many Thermomix owners also sell them, it's pretty hard to get unbiased information online so I'm wondering if a speed drop of nearly two thirds will make a difference to the smoothness of my purees. From demos I've seen it think the Thermomix will do a better job with curry pastes and spice grinding as the blades nearly touch the base of the container unlike the other two units: my thinking being that however high the rpm of the Vitamix/Blentec, if the teaspoon of spices can't come into contact with the blades, it's useless.

I read the What to look for when purchasing a blender? question and found no mention of rpm so maybe it's a parameter that isn't very useful, if so then it would be nice to know that at least.
I've used both a Vitamix 500 (not extensively) and a Thermomix TM31. I didn't know there was a difference in RPM, but I didn't notice too much difference in end-effect when both were turned up to full power. So I think it doesn't make much difference at those speeds anymore.

If you're having trouble milling spices though, it helps to heat them a while in the oven, to get rid of humidity and therefore make them more brittle.