In four words or less: Hybrid of Bitcoin and Ethereum
Properties of QTUM:
Qtum (QTUMN) is a decentralised smart contracts platform and value transfer protocol. Qtum can be viewed as a hybrid between Bitcoin and Ethereum, using the Bitcoin blockchain for settlement, and running a second layer for computation.
What problems does QTUM solve:
Qtum solves the problem of speed and scalability using a network offering fast distributed computation and settlement. Qtum is working on building a Lightning Network that can reach as much as 20,000 transactions per second.
Adoption and Penetration:
Qtum nodes have grown continuously in the past months, showing an increasing adoption. QTUM was seen as a competitor of NEO, Ethereum, and other similar platforms with distributed computation and smart contracts. However, Qtum may be limited to Chinese supporters. Trading of the coin is concentrated on LBank, ZB.Com and other niche exchanges, for now missing from larger marketplaces.
Risks and Limitations:
The Qtum market price is volatile, rising as high as $70 and then falling under $5. The other risk is that QTUM is just a year old, and has yet to show a viable ecosystem of distributed apps and real-world applications.