My name is Alexander Chepurnoy aka kushti. I'm working as Nxt core dev and proof-of-stake researcher. I also helped some startups(SecureAE, SmartContract) in the Nxt ecosystem with consultations & code and made some proof-of-concept applications on top of Nxt(e.g. Cryptamail secure messenger made for Techcrunch Disrupt Hackathon NY 2014).
I also worked as an app dev with some Bitcoin implementations e.g. Bitcoin Core (bitcoind), BitcoinJ, Toshi, Btcd.
In comparison with BTC NXT has much simpler transactional model. No multiple inputs & outputs, dedicated accounts.
With all Bitcoin protocol implementations(except of Toshi by Coinbase) it's even not possible to get transactions list for arbitrary address without
making a lot of work building own datastore solution. Working with Nxt you get such a thing out of box!
Nxt is the platform, not just a currency. So to build an app using a decentralized assets exchange you dont' need to get into Bitcoin & CounterParty reading about proof-of-burn on the way or Bitcoin & Colored Coins w. MasterCoin protocol, Nxt AE is the part of the Nxt, so just use the same API for both financial operations & assets-exchange-based business logic. The same is true for aliases, monetary system, voting system etc.
Any transaction could has appendages, e.g. public or encrypted message with up to 1000 bytes of data. Remind the Bitcoin devs about raising OP_RETURN max data size from 40 to 80 bytes. There are a lot of ideas to store business or government data into the blockchain(contracts, documents etc). With Nxt you can turn these ideas into products right now!
Nxt is the exciting choice to build blockchain-based applications already chosen by many startups!