If I would buy on margin, there would have to be a pretty decent pullback. If the value drops below 20%, you get margin called. That 20% doesn't afford you a ton of wiggle room. I shorted Monero not too long ago. The damn thing was too volitale so I jumped out of it. Lesson learned.
That's true, margin can be really dangerous. However there are ways around some of the dangers. I've been all-in FCT for a month or two now, and recently got bored, moved all my holdings into Margin, and am now using that as leverage to buy more FCT. The key: I only buy about 15% worth of the holdings I've moved into Margin, so will always have more than enough collateral to avoid a margin call. I have to pay the daily fee for borrowing the additional FCT (right now about .009%), but aside from that, I believe FCT will rise sooner or later, so it's really just a matter of doubling down, with the relatively small borrowing fee tacked on. Not recommending this to anyone, just ... FYI.
Im trading margin for over a year now and days like today can give you great profits, if poloniex would like to get me out of my margin then need to trow in more btc then they ever can win from me.
Btw if you are long on fct you actually dont borrow the fct, you borrow btc for that so your rate should be much higher. Unless your shorting fct you can see what your lending on the lending page.