I used the "Secret Hot Rate" option with pretty good luck in the past, so I decided to try it again for my upcoming trip. If you do sufficient research on ratings, amenities, and regular room charges of certain hotels within a given area on this site and others, you can get a fairly good idea which hotels are likely offering the special rates on Hotwire.
And that's what I did in this case. I looked around for the lowest rates on reservation sites that do identify hotels upfront for those hotels I thought were offering a secret rate to see if any price differences were worth taking my chances on Hotwire. I decided to take my chances and guessed right.
I initially thought I paid around 15% less than the lowest rate offered elsewhere. However, I then noticed that the additional taxes and fees on Hotwire were about 50% higher than on the other site, which reduced my overall savings by nearly half.
So if you do try to narrow down the likely hotels offering a secret special rate on Hotwire, consider the rate as well as the additional taxes and fees to see if its worth it.