There is plenty of information and consternation in the Wi-Fi Update thread.

The definitive way to tell if you're receiving "premium" service is with two devices.

On device #1, login with your Diamond credentials. On device #2, purchase premium internet. Go to www.speedtest.net on both devices and see which is faster.

In my recent experience in various Hampton Inns...

1. Both devices will register the same speed test results. This means that Diamonds are getting the same speed as purchasing premium service. This is the case in the HI I'm in right now. Both devices are registering 2.5 Mbps down and 1 Mbps up. I laugh at paying any amount of money for such horribly slow service, but it is what it is. The front desk always refunds the fee at check-out.

2. The device with purchased premium access will test 2-4 times faster than "Diamond"-level internet access. This means Diamonds are not receiving premium service. I complain at the front desk and get the premium fee refunded. If it happens again in subsequent visits, asking for a full refund is reasonable since they guarantee 100% satisfaction.