Hope you are doing great.
Which would be a better choice between MongoDB and Cassandra going by current popular demand? Which one you suggest would be beneficial?
Answer: Both of the databases are from NoSQL family. Both are good in their field.
As far as I know Mongo Db is trending now, however it completely depends on you and the skill set that you have , to decide which will be more beneficial for you. Please go through the below link.
They list the similarities and differences between cassandra and mongo db along with their characteristics:
I hope this answers your query. Please let us know if you need any further help.