I think POS better than POW.
PoW is bad for the environment and as soon as you launch even if its asic resistant the botnets move in and rape mine until the difficulty rises so mere mortals with home computers and laptops lose out.
If you want to do something good for the world - copy what ripple has done which I think it quite smart - put part of NEM 10,20,25% I don't know up for World Computer Grid stuff over a period of time e.g. 6-12 months.
People download the computer grid stuff, join team NEM and let the research projects around the world use their PCs for research computations that benefit us all. We read the team stats (which they can't fake) off the computing grid team stats page and award NEM every 24hrs as a result.
Its much more in line with the sense I have of the 'New Economic Movement'. My desktop at home is earning ripple when I'm not using it, has been since december, probably makes 60 xrp a day - I'm not covering the electric costs probably or making huge money and for the Ripple alone I wouldn't do it but I like the idea of helping the research projects too i.e. doing something good with the spare PC capacity.
You could market it as well ....
And because there isn't a 'pure' profit you don't get the botnets and the other professional miners moving in with their high end kit.
It has been discussed elsewhere but it is important t to mention here again. PoW has a big problem when mining power is concentrated. With a 51% of mining power, you can really control the currency (you can authorize or not transactions); thus, you trasnform a descentralized system into a complete centralized one. Actually, the investment required to control 51% mining power of Bitcoin is about 5% of the current market capitalization of Bitcoin; which for a company or a government is quite cheap.
PoS solves that problem. To control the currency, you will need to buy 51% of the total amount of coins released for that currency; which is obviously very very difficult to obtain The problem of PoS is its unfair distribution and the bad incentive to exchange money. So, I/m very curious to read/known more details about NEM's implementation. If the Proof of Importance succeed, that will be a major hit of this coin