I don't understand this part. What do you guys mean by "they don't give big wins"? 
I didn't understand this part as well to be honest. I have observed many people win big amounts from Roobet which is why what they stated doesn't really make any sense. Yeah, big wins happen on Roobet all the time. Here's just two latest ones:
Btw, I suggest everyone to join the army of their 156.1K twitter followers. Lots of interesting stuff is happening there, including giveaways and challenges with good prizes.
And as someone who played "Guess the Slot" a lot here on bitcointalk, I can say that the game is much easier on twitter, just look at the yesterday's challenge, for instance
If you play slots, you can say the answer right away.