I saw it riddled with HTML errors, there were buttons that didn't do anything, I got (html) responses that were false, which I only knew was the case because I looked directly at the API response.
I remember I 'sold' some litecoin on Coinbase that never sold. Took me to a couple days just to know it wasn't going to mysteriously disappear.
I find the fact that they want to add new coins even though they haven't solved any of their current issues very alarming.