Hi Cheekwit,

I've only heard of them, not traded there just yet.  But I'm also interested so will look forward to seeing others reply to your query. I've tried 100x leverage on Bitmex but I don't like the platform itself.  Too many errors and was unreliable which as you can imagine is very frustrating when it's your cash on the line...I don't have the time or strong enough nerves for that crap.   

PrimeXBT looks really good and I've seen some excellent reviews.  I would also be keen to use 100x on more than BTC alone... EOS and LTC are my favourites for day trading.

Let me know how you go if you do try it. Good luck.