Qtum is QTUM, ETH is ETH and NEO is NEO there is nothing like next ETH or Ethereum killer.
ETH is backed by many big companies and who is backing qtum? ETH is also a tried and tested platform so why one need to use Qtum instead of ETH. And also we still don't know about Qtum's security (Though ETH has been compromised once)
and as for the security qtum is planning to send its satellite to not to use internet. can you imagine the level of security which neither eth nor neo has. i am really impressed.