I too didn´t use a UAT and have good results... however it must be mentioned that the UAT has two advantages over the header tank.
The first one is a screening tissue that acts as a filter, and it is better than because it is a lot less prone to get clogged due at it´s bigger area compared the the standard filters.
The second advantage is that the UAT still works even if a large bubble is developed inside it, acting as a warning that something is wrong in the plumbing or in the tank setup... instead of a large bubble on a header tank that means a instant turbine flameout.
Seems that it is not senseless at all to pay $65 for a plastic tank...
Enrique