The theoretical limit lies at 4 billion notes. But of course that's theory) I've tested CintaNotes to run on a base with 10000 notes, and it runs fine. But for the current version I don't recommend running CintaNotes directly from the flash drive in this case - it will be slow. Right now CintaNotes keeps the whole notebook in memory and saves it to the disk each time something changes. This is of course quite inefficient, and I'll change this in one of the next versions, where I plan to migrate to an SQLite database. Hope this information will help you to make a better choice (see here).CintaNotes seems to me one of the closest equivalent of nVALT on Windows.
In recent months have become more and more interested in the actual capacities of note-taking software. For a life-time of note-taking, two things seem to me essential: (i) the ability to handle tens of thousands of notes easily and effectively, (ii) the ability to import and export notes easily to other formats (most importantly [for me] in text format).
In some sense I like ResophNote better, since it uses the convention of '“internal link” with [ and ] (wikilink)'. It's also closer to nVALT. But I am not sure about its limits.