When the WB came out, I got tired of hearing all the hype. I just knew there was no way a rest designed like that could be efficient. I was even one that used to say, "the only good biscuit is one with gravy on it." Then I decided to test it and several other rests using a Hooter Shooter machine to get a fair study.
Here's the bottom line. I ate my words to all those WB shooters! The ONLY difference the WB has is an insignificant slower fps than the drop away rests. It averaged 2 feet per second slower than my Trophy Taker rest, Rip cord, and Muzzy rest. The WB also shot absolute perfect holes through paper, and with 2" Blazer vanes shot broadheads exceptionally well with no vane damage over extended shooting periods.
I also dunked the WB bristles in water and froze them in the deep freeze. After several days of being in the freezer with some iced bristles, I quickly shot it through the Hooter Shooter and looked for any differences. There was none. So again, I had to eat my words.
It's a very functional rest that, if tuned correctly, will shoot very well and not cost you fps. It's simple to use with no moving parts. However, I found you need to shoot smaller vanes (Blazer Fusion, etc.), as the larger length vanes tend to wear out after numerous shots. Overall, both types of rests work well. Just my opinion and results from an unbiased test.