I have one and I don't use it very often. I did come in very handy when we couldn't find the coffee grinder. I have used it to grind wheat berries but the result, and the resulting bread, is a bit grainy. In order to get the wheat fine enough to use the vitamix has to be on so long that the friction causes the flour to heat up. I can see it getting burned if I'm not careful. Another thing I have found is that for some reason that I can't wrap my mind around flour, even whole wheat organic, is less expensive than wheat berries. I have no idea how that could be but that alone is enough to keep me from grinding my own wheat. To me, it's more of a novelty than anything else.
I have yet to come up with a really useful purpose for it but I'm still looking.
I got it at a state fair for $75 and I feel I paid too much for what I use it for, unlike the wet container which I use all the time. I'm thinking of getting a wet blade to replace the dry blade in the little one so I can make small batches of smoothies and sauces without dirtying the big one. The thing I got that I really like is the special vitamix spatulas, they were free at the fair and are just right for getting everything out of the tall container.