I guess it comes back to what you can afford and where you come from too. I have always been a middle of the road kind of guy. I don't buy the cheapest, but I also refuse in most cases to buy the most expensive. Some people throw money to the wind, some bargain hunt.
From what I know though, I don't think anyone buying the most expensive stuff for their tank setups is wasting money. In fact, my only major complaint is the ADA tanks. But do they look amazing? Sure do. I just have never seen, and probably never will, a real side by side comparison of a lot of this stuff.
Seems like reputation is king too. Everyone knows what is cheap, what is middle, and what is top of the line.
And that goes for a lot of things. Someone might build up their vehicle for speed and spend $1000 on something that may only gain them 1HP, and people would probably scratch their head at them LOL.
I considered an ADA tank I saw for sale on here. Even used it was still the same price as a Schruber Wright (sp?) or Aquatop LOL. But I would have taken it, just never heard back from the person.