More or less, it seems most all systems are essentially variations on the Brewtus systems.
The traditioanl valve to use on these systems are ASCO valves.... those used to be cheap to get because they were so widely available on E-Bay as surplus from industrial places cleaning off their spare parts shelves. Over time, the stocks have eroded, and they are much more expesive of E-bay now (closer to retail price), so many people are moving toward cheaper alternatives.
For the home brewery, the ASCO valves are way overkill. Mean time between failures is in the millions of cycles. Cheaper hobby level valves are becomig more popular which are still good for 100ds of thousands of cycles... are better priced and for our purposes, just as good.
Fundimetally, there are different valve constructions. some are "globe" style, which pushes a seal down from the top with a spring, and uses an electric actuator to pull the stem up and over come the pressure of the spring to open the water flow. The issue with the valves, is that if you supply back pressure, that will also over come the spring, and allow water to flow backwards through the valve.
Ball style valves work differently in that they move a ball with a hole in it. This style does ot have issues with back pressure causing the valve to open up when it is not supposed to due to the differnt mechaical design.
In the system I have, I have two paths into my pump, and two paths out of my pump. What path the water takes going out of my pump....depends on what valve is open. When I had globe style valves installed, I had things connected in a way that the back pressure would allow wort to wind up in some un-intended places. Once I went with ball valves.... that eliminated the issue from happening.
The globe style valve issue may have been correctable by flipping the valve 180 degrees, but I elected to go with ball valve style to make it more idiot proof. My thought was that installing and removing valves on my system is a real pain (kind of like changing the oil in a car with the way I have the valves stashed) so if I was going to re-do it, I wanted to make sure I did not have to keep messing with it.
My advice is if you are buying valves... go ball and keep things more idiot proof. The cost is about the same.