I purchased prepaid card from Clay for my trip to New York from May 2-17. I took their 15 days plan. It never worked a single time in New York. There was no network coverage. While in US, I went for Washington DC for a day and I could get network at some places.
Overall, it was total waste of money. I recommend people going to US to buy sim card locally as you would get a better and working product instead of buying from India. I would not recommend Clay sim card to anyone.