speed alone is a horrible metric to judge database systems on, and to be fair just about ANY database system will be able to run "fast" with a low set of data.
if you want a database to be scalably fast, that is, fast even when operating under a large load of entries, you need to know how to design indexes, and how each option of database handles indexes, since those are a world of new ups and downs to deal with.
for example, RavenDb performs indexing work in the background which means that it will always have an index ready for use but the index may produce stale, or out-of-date results.
i wouldn't go so far as to say that NoSQL is better than SQL, because SQL has some strengths that document stores or simple key-value stores simply don't have due to design.
buuut, you said you're not planning on publicizing your server., so like 70% of all database features and caveats don't matter to you. hell, you could even store your data in app memory itself and just flush out to text once in a while