Thinking of switching to Dark Star from Visible premium

Mainly because I have no service at work with visible. There's one thing I can't seem to find an answer on, I don't really care about hotspots, but I do care about having unlimited data speeds that don't get throttled down to unusable speeds after a certain amount. The main reason I use visible is because of this, is Dark Star truly unlimited or will it cap my speeds after I use a certain amount. And if so, is it different between the unlimited premium and unlimited starter plans. Thank you.