SharedPreferences vs SQLite vs NoSQL

If you have data that are

• appended several times a day
• often with the same or similar content
• small for each single entity, but can grow to more than 1.5M after some use
• currently accessed only on a by-entity-basis, but should be queried/filtered in further versions

which storage option would be a good fit?

As a tracer bullet approach, SharedPreferences had been used in the UI thread, but this can slow down the app.

Care could be taken to make the SharedPreferences calls in another thread, but maybe it is time for a more adequate solution, like SQLite or NoSQL.

Currently, SnappyDB seems like a good fit for NoSQL, although the integration of SQLite into android ListView is a plus for SQLite.

Which approach would you recommend?