Bought one a few weeks ago. For $100, the quality is somewhat disappointing. Also I had to affix a small weight to the flapper as the nozzle would continuously drip. The weight of the flapper alone does not provide enough "oomph" to shut valve completely (water pressure around 65 psig). It solved the problem but it should have never been required. I will be surprised if this thing lasts any real length of time.
Plus $30 for the tiny filter!
On the plus side, I'm 100% sure it increases efficiency of AC unit.