As I understand it, the fact that a) Lisk uses Javascript for DAPP development and b) Lisk DAPPS will each run on their own sidechain, are 2 great advantages of Lisk over Ethereum.  Are there other advantages?  And to be fair and balanced, what about disadvantages of Lisk vs. Ethereum?

Also, are DAPP sidechains secured by the Lisk network, or do the sidechains need to have their own block signers?

Thanks in advance.  Very exciting project!