I'm not going to quibble. I think the prize amounts are too high and I don't agree with their "direction". I do support the idea of govt prizes. The idea that they would cheaper than NASA and the program doesn't compete with NASA, I wouldn't disagree with- though I'm tempted to quibble this point.

I like the idea of govt paying a billion dollar for first ton of water mined on the Moon. I wouldn't be too upset if the monetary amount was higher: 2 billion or even 5 billion- at least it's in the right direction.
As far as tax dollar value, I think it would be very cheap if govt kicked in some money in the X-prize (maybe a bit late in the game, but better late then never). I think it's in the govt (tax payer's) interest to encourage private prizes. One way this can be done, would be for govt to match funds- turning the 10 million prize into a 20 million prize.