My full sized system is from rex griggs. Its a little over 3 years old. It was setup on just my 55 gallon for most of its life. For the last 6 months its been setup with the two lines. There is a 3rd port on the back side, since its not in use it has plug there instead of a hose barb. Then I use inline needle valves, and bubble counters. Its 5lb tank lasts at least 3 months running a 20 and 55 gallon.
For what it is its decently priced. You could customize a beverage regulator to do the same thing for cheaper. Most aquarium regulators are just glorified beverage regulators. Regulators themselves are pretty long lived devices. Given the easy life a hobbyist regulator has compared to a commercial one they should last many many years. Only difficulty with DIY pressurized it to make sure threads match and what not.
I would avoid any really custom manufactured regulators. My red sea paintball system is a good example of what to avoid. Its going on 5 years, which kinda impresses me given how much plastic it is made out of. However once that reg eventually fails, its basically garbage or scrap. I doubt I could repair a regulator like that one as I doubt it uses common parts. Most commercial type regulators though are pretty easy to fix with interchangeable parts. Pressure guages, valve stem, and output fittings all just screw into the main diaphragm, which can also be disassembled. A $50 premium or $30 cheap/used beverage reg can be pretty easily converted to a aquarium reg if you take off its original output barb then use the correct adapters. You could directly attach a solenoid, needle valve, ect. You just need the correct adapters.