to be clear Im not a NXT shill.  I'm a cryptocurrency expert.  I got involved with NXT fairly recently.  The NXT model is far more lucrative than Bitcoin.  I've also been involved with the PPC community and I've worked on other algorithms in the past.

PoW has not been 'proven' to do anything.  It's just that we've never seen it be exploited to any significant degree.  And it's possible to purchase this protection for so long as the insiders can afford to monopolize the hashing power, or the reward for hashing honestly is higher than the reward for hashing dishonestly.  That monopoly is very close to being broken.  In addition, as block reward gets smaller, the hashers must pay for electricity via transaction fees.  In a recent earlier post you displayed an ignorance of this fact.  It's very very important.

Bitcoin will continue to 'work' only for so long as the block reward continues to be valuable enough(in real terms) to offset an attack.  We are very close to this threshold and color coins just might push it over the edge.

go and have a look at NXT for yourself, then decide.

-bm