Hi,
I’ve bought the Forex Grinder expert advisor 3 weeks ago.
It is actually 2 robot: scalper and “regular”, and I’ve put both on my account.
Even though I left the “Max risk” parameter on its default 1.0 the first trade have lost 20% of the account. Yes, that’s not a typo, a twenty percent loss 
They didn’t bother to supply a decent user guide, just a PDF file with 3 pages in it.
All in all, this is probably one of those scam robots, and I’m disappointed.