I used the Chase UR portal to do some online shopping the same day I got CSP. The first day's transaction went through for about $100. The next day I made another $200 online purchase with that merchant (free shipping can lead to inefficient planning, I know
The second purchase was initially approved, then declined a few hours later. Having heard great things about CSP's service, I assumed I must have just entered the card info incorrectly. I thought Chase would surely contact me immediately (either by phone or email) if something suspicious was going on. Discover did that, after all. So I tried to make the same transaction again. Once more, it was initially approved then declined a few hours later.
I then called Chase, where I waited in line for 10-15 minutes before I spoke to a live front-line representative. They transferred me, I answered some security questions, and they put in place a sort of "fraud detection override" on the card for a day so I could make the transaction.
That was not a smooth experience, but I've had no problems with the card since then. I've made a few transactions for around $1k, but nothing really huge.