Peershares could also be considered:
http://peershares.net/general-information/It has not yet been released, but the ETA is relatively soon and the platform would fulfill all our needs.
I have doubts about NXT, because of how centralised it is; it does not seem much better than Cryptostocks. Coloured coins would be a necessity for me to consider this option.
I didn't know about Peershares. That's interesting but it is not ready.
There is also Counterparty Protocol and MasterCoin but it is not fully operational too.
Nxt is simply the most decentralized cryptocurrency.
It is Proof-of-Stake : no 51% attack possible. Nodes are dispatched around the world. There is no pool that centralize hash (forging).
It is the strongest Proof-of-Stake coin.
There are different forums.
There are different clients available.
Having assets or currencies on the Nxt blockchain is the safest existing place.