What is the purpose of the application? To give advice on what NoSQL database to use that is necessary information. For instance:
1) Do you need ACID transactions?
2) What is the ratio between R/W?
3) Throughput (how many R/W per sec)?
4) Number of simultaneous users?
5) Environment (Java/Microsoft)?
6) How do you plan to connect to the database?
There are some great options in the NoSQL/NewSQL market but all databases have their pros and their cons.
If you need a transactional database that has the same level of transaction security and ease of use, I would go for a memory centric object oriented database. Even if they are memory centric they often secure all transactions on disk to fulfill the ACID (D=durability). Depending on your environment there are some options.
You can take a look at Starcounter that gives you true ACID, works In-memory, have a very easy to use API, easy to connect to and have extreme performance.
If you need Linux and Java environment for your servers, there are other options!