Not always positive - but been doing well every week so far 
Statistically positive
That's why the investment is always a cool thing in a casino ^^
Btw, I got a question. Is there anything securing the invested funds?
Your coins are as secure as you are holding it in your hands. You can trust admins of the site as their own bitcoins are also invested in the site.
Yolodice is growing day by day. YD have made around 85 btc profit since its launch.