The price is the kicker indeed. For those of us used to buying non-tube amps at a much lower price, these do look pricey. I suppose the other way to look at it, though, would be that they're markedly cheaper than the all-tube original amps they have - e.g. c/f the 'normal' Twin Reverb with the price of the Tonemaster... so if the alternative was looking at those, then it is a saving. I'd love to know the cost difference to Fender in production and how that works in to their pricing strategy, given that there's still obviously R&D costs to factor in to the Tonemasters as they're fairly new, whereas the tube circuits they've been building for decades.... If it gets popular enough, I'm sure we'll see it filter down to more affordable options, in the same way that thirty odd years ago or more Peavy turned out their own range of tweed amps at a very competitive price vs the Fenders.
The Vox 'nutube' tech is interesting as well, I'm intrigued as to whether that will take off. I don't know anything much about the tech and how it works, though giving the player the notion at least that there's a sort-of direct equivalent of the traditional tube in it might help persuade some of the 'four legs good, two legs bad' crowd.
The other question of course is how long the idea of the traditional amp lasts for live use. I'm hearing of more and more players going the 'amp sim pedal to PA' route. The sort of Champ you describe could be a really great way of marketing that sort of convenience with the idea of 'authenticity' bundled in. What the really big artists are doing will, of course, reman influential...