Dude, nothing was rewritten from scratch, just a few bits and bytes were tuned left and right, don't get yourself into such arguments when you never even looked over the code :-)

You should really stop that nonsense, I wish good luck to SPR, it needs it, but you cannot compare it at all to Darkcoin..

Is SpreadCoin [masternode] implementation based on DarkCoin?
No, this is original implementation.

How is it different from DarkCoin?
In SpreadCoin there are no centralized reference nodes to decide which masternodes should receive payments, it is decided by the network in decentralized maner. In DarkCoin the messages which select masternodes are separate from the blockchain and are distributed independently. This way it is possible that nodes will have different opinion on what masternode should receive next payment. In SpreadCoin all votes for masternodes will be stored in blocks and the payee will be uniquely determined from the previous blocks. Just like you can check that any transaction included in the block is correct by comparing its inputs with outputs in previous blocks you will be able to check that masternode payment is correct by checking previous blocks. Why bitcoin is so reliable? Because all nodes have exactly the same rules how to determine which blockchains are correct and which one is better (required more work) than others, these rules are only depended on blocks themselves, not on the order in which they were received them nor on any other messages which you may or may not receive in time. The network can be unstable in the case of some major event which will break connectivity between nodes but once connectivity between nodes is reestablished all nodes will stick to the same blockchain. The same will apply to SpreadCoin.