I participated in one today.  My first ever.  It took me 20 seconds to get my order in, and by that time it rose 110% , so I decided to just buy $18 worth.  After 10 seconds , I figured it was going to quickly fall , so I sold for a 10% gain. $ 1.85.   Sure enough , a minute later it dropped 60%.  

     I don't think these things are very good for any one except the people that run them.  They probably buy their coins days in advance at good prices and already have their sell orders in place before it starts.  They really don't have to worry about losing anything.  It seems a bit unethical to me.  We sell at highly inflated prices knowing it isn't real at the expense of others that end up losing big.  

             For everyone except the owners,  its easy to get hurt in these .   I would have lost 50% if I would have held for another 45 seconds.