QTUM looks very interesting. How will it compete with Ethereum and Lisk?
Don't think it is strictly out to compete with Ethereum, guess it is seeking to fill the void. From what I can make from its articles, I think it has the making of a bridge between the best of Bitcoin and Ethereum - more or less a hybrid of Bitcoin and Ethereum. Given the strength, acceptability, capitalization, in fact, the antecedents of the two, I think we are at the threshold of a new frontier, only pray if all get well coordinated.
I think it rather competes with rootstock and in the 2nd place with ethereum like rootstock.
It's based on bitcoin like rootstock with ethereum-style smart contracts.
most interesting part to me is the compatibility with already existing ethereum contracts and other stuff.
Each of these platforms will be unique, but they will also have a lot in common. The article above also coincides with my opinion that this two projects worth attention in 2017.