Another difference between the two is the different proof of work algorithm. (coinstocks.com)
Each transaction block of the blockchain is written to the decentralized ledger by a main node, which is selected using Proof of Work - like calculations. (cryptocoinspy.com)
The roadmap set out was three to five years to achieve this, it would also involve a change from proof of work to proof of stake. (dailybitcoinnews.com)