Power Dump Valves

What do you all think? Are they worth the $. And are they tough to install? Also is it worth installing them on the Gray water tnk/s?

I installed one due to the fact of how the plumbing was installed by the factory (you can see photos in my link below). After I installed it the first time, it didn't work properly due to the angle I installed it and that was the reason to change the piping and I reinstalled the valve. I do have a second valve I plan to install on the grey water side and use two switches (one inside and one in the basement) because the grey tank fills up pretty quick with 5 people. I need to by 2 switches and the 1-1/2" to 3" adapters.