I've been having a lot of trouble with their servers lately. I don't think they're capable of handling those days when the market is trading at an extremely high volume. Their servers went down and their app stopped working. What is the other platform you're using?
I am now using an exchange called Gemini. But I also store whatever I purchase in a wallet. My wallet choice is Trezor and it seems pretty secure. Well if anything is secure these days...