Blockstream is a blockchain technology company known for its work on Bitcoin and related technologies. However, the legitimacy of Blockstream can be subjective and depends on individual experiences. Some users have reported positive experiences, praising its reliability and the range of services it offers. On the other hand, there are also negative reviews, with some users reporting issues with transactions and customer service. It's important to do thorough research and exercise caution when dealing with any company in the cryptocurrency space. Remember, the nature of investments in this field can be high-risk. Always verify before you trust.