They often have quite weird spikes near close and open. Even got...

They often have quite weird spikes near close and open. Even got stopped out of stocks there at prices they nowhere near traded at. Very annoying. Now I always make sure that I cancel all my stop orders before the market opens and put them back in later, just in case I have a longer term position with them. Mostly use other providers for that these days though as it is much less time consuming and you don't have to be there for the open all the time.
CMC is good for daytrading, but apart from that I don't trust those spikes.