Maybe you can check out a thread of Jamber.io which was created here by one of the owners, i think;
https://bitcointalk.org/index.php?topic=4667343.0You can read through to get a clear picture of the discussion.
As for francex.in, i have never heard of it. if the website or service is brand new... don't waste time with it.
Yes, I also think that whatever you find from darknet is
"more likely than not" to be a scam. And when I was also checking Jamber I also didn't find any actual feedbacks from investors. The thread is mostly from user side and only few ppl asked questions about investors, but didn't really say if they tried investing there.